Professional Wrestling itself is almost always this trope, excluding the periodic boom periods note The mid-'80s, which brought us Hulk Hogan and the Rock & Wrestling era where it becomes okay to admit that you're a wrestling fan without getting called a redneck. Of course, even when wrestling is on the low, wrestling companies still tend to be relatively successful. Fans cry that the end is coming far too often however.
WCW. Once a dangerous threat to the WWF, it quickly fell apart due to catastrophic mismanagement, eventually being bought out by its arch-rival for scraps, and its disastrous final years are what many wrestling fans today think of when they hear the promotion mentioned.
The Monday Night Wars put an end to shows made entirely of Squash Matches. Once shows presented quality matches on free tv, fans of either company wouldn't settle for anything else. While some may have a squash match or two to debut a new wrestler or for a joke match, a show consisting entirely of them will suffer in the ratings. And if you're a younger wrestling fan (say, ages 10 to 30), you might not even be aware these shows ever existed.
The rise of cable television (such as TBS and the USA Network) and the World Wrestling Federation's successful national expansion (and to a lesser extent, Jim Crockett Promotions/World Championship Wrestling once Ted Turner came into the picture) in the 1980s, all but put an end to the concept of territorial wrestling promotions.
In particular, the collapse of the Memphis-based USWA (United States Wrestling Association) was probably the final nail on the coffin. From its founding in 1989 until about 1995, USWA managed to make a name for itself in spite of the WWF's explosion by focusing on up-and-coming wrestlers who were looking to launch their careers and eventually join the "Big Two." Unfortunately, the Monday Night Wars dealt a significant (pun not intended) blow to the company, as they lacked both the talent and the budget to compete with the almost Pay Per View quality matches being presented on Raw and Nitro. Not helping matters was an ill-advised move to Thursday nights for their wrestling shows. Things became so bad, in fact, that by late 1996 they were reduced to doing shows in front of less than 400 people at a flea market in Memphis (if you're curious and/or masochistic, you can watch one of their final shows here: https://www.youtube.com/watch?v=iq-PNas37j4). Combined with a rather poor lineup of wrestlers, the generally poor quality of its matches, and the fraudulent convictions being allagated to the company's management; USWA folded in late 1997 and is now largely forgotten by all but a few diehard wrestling fans who remember them as a perfect representation of why territorial wrestling was unable to survive the Pro Wrestling Boom of the 80's and 90's.
Organic tag teams are in a severe dry spell. Tag teams that consist of people hired together specifically to be a tag team, often two people who are related (the HardyBoyz, the Steiner Brothers) or good friends who have wrestled together for years (The Dudley Boyz, Edge and Christian) are increasingly the minority. Strangely enough, the majority of the blame can be placed on Shawn Michaels of all people. When the Rockers were split up, he went on to become easily one of the biggest wrestling names of the past 20 years. The big companies saw a massive star rise where a tag team fell, and have systematically broken up every organic tag team they have in the hopes of making lightning strike twice (and because "brother against brother" is such easy drama, the storyline writes itself). The tag team division is kept afloat by throwing together two random singles wrestlers together, and since WWE doesn't seem to think too highly of tag team wrestling it the first place, this doesn't appear to be changing any time soon.
It should be noted that this wasn't originally supposed to happen. Both Michaels and his partner, Marty Jannetty, were supposed to become stars, being considered equals in charisma and in-ring talent. Unfortunately, Jannetty's partying lifestyle caught up with him and he never got over. The fact that "The Shawn Michaels Effect" has occurred so often with these tag teams is the main reason why organic tag teams are in a dry spell. The Hardy Boyz, Edge and Christian (though that's arguably a subversion seeing as while Edge is the bigger star, Christian has won more independent titles and achieved what Edge was never able to do — become a Grand Slam Champion), even the Dudley Boyz have all had this happen in some shape or form and a bonafide star was made with one of them. Let's face it; the moment it became clear that Shawn was gonna go farther than Jannetty, the devaluing of tag team wrestling was all but inevitable.
Pay-per-views in the growth of the internet age have become dying form when people could get live results as the PPV was happening. That doesn't even go into the illegal live streams. PPV purchase numbers continued to shrink year after year. In 2014, the WWE caught wind of this growing problem and decided to launch the WWE Network, an wrestling online streaming service equivalent to Netflix, that offered Pay-Per-Views as part of the package. Cable companies were not happy with this, but the WWE ultimately looks to be benefiting from this new service.
There was a time in the late 90s when garbage wrestlers were more popular in the 50 States than standard professional wrestlers. So popular that millions of young wrestling fans started having brutal matches of their own in their backyards. However, ECW folded in 2001 and within the next few years the hits just kept coming. First there were the various lawsuits from the parents of kids who maimed themselves imitating what they saw. Next Mick Foley (the most famous hardcore wrestler of all time) had to retire from active competition due to his various injuries. Then the rise in awareness of blood diseases like Hepatitis caused most pro wrestling companies to stop their performers from blading (cutting themselves on the forehead to draw blood) and blood was a major part of the attraction. Finally the death knell was the Chris Benoit tragedy, which caused major investigations into the WWE and pro wrestling in general. Due to the pressure of these investigations, WWE moved toward a rated PG product and banned weapon shots to the head. There still exists some traces of it like an annual Extreme Rules pay per view in WWE which features a watered down product and the indie company Combat Zone Wrestling, which is mostly looked down on by wrestling fans in favor of Chikara and Ring of Honor. Hardcore wrestling in the USA will likely never reach its old heights again thanks to safety regulations and a whole generation of wrestling fans coming of age now who have likely never seen a hardcore match.
T&A style matches in place of actual women's wrestling. The concept was introduced by Vince Russo as a way to have Sable in matches without having her wrestling (since she was a model, not a wrestler). Fans weren't used to seeing such beautiful women getting physical in a wrestling ring, so it was relatively popular. These days however, WWE has gone PG and any attempt they've ever made to have Fanservice matches inevitably gets backlash. This is due mostly to WWE no longer putting untrained models in the ring (every Diva has to train in developmental first) - and numerous examples in WWE, TNA and indie promotions showing women putting on stellar matches. The casual fan these days wants to see actual women's wrestling, as well as interesting characters beyond a Ms. Fanservice. Case in point: Eva Marie got booed out of arenas for her lack of experience. In the Attitude Era, she would have been as popular as Sable, Debra, Terri, The Kat etc.
Gorgeous George rarely works as anymore, at least as originally intended. While they still pop up from time to time, merely being Ambiguously Gay isn't enough to get the crowd to hate someone, as Paredyse in Ohio Valley Wrestling taking up a gimmick similar to Gorgeous George and while not outright admitting to being gay, is directly attacking gender roles. Goldust before him had to add on a bunch of bizarre mannerisms in addition to merely being ambiguously gay, and this backfired as people ended up taking it too personally, leading to threats from gay rights groups. Thus Goldust "had" to come out as really straight in order to protect the WWF's image, as an ambiguously gay heel would tarnish it more than an incest angle.
Wrestling magazines such as WWE Magazine, Inside Wrestling/The Wrestler, WCW Magazine, Power Slam, WOW Magazine, and Wrestling Superstars have pretty much disappeared thanks to the rise of the internet. Pro Wrestling Illustrated remains though and a few organizations such as the National Wrestling Alliance have retained theirs.