Comedy team Bob & Ray are subject to this to an extent: now that the Deadpan Snarker is ubiquitous and subversion an essential part of the American comedy landscape, it's hard to realise just how cutting-edge hip B&R were considered for popularising and refining those elements back in The '50s. Partly because of their unassuming style and partly because, as one commentator put it, they influenced a lot of people who've become a lot more famous building on their innovations, not incidentally including Seinfeld himself.
The Howard Stern Show. What once was an audacious, subversive breath of fresh air among radio DJ shtick, only Howard Stern himself stands out from his many, MANY imitators because of his reputation, and even that's taken a hit in recent years. Even the move to uncensored satellite radio hasn't stemmed the tide of "So What?"
Adam West - yes, thatAdam West - hosted a radio show for a brief period in the early '50s, when his name was still Billy Anderson. While he didn't blatantly take credit, he described what he was doing as "early, less crude Howard Stern." Funny thing is, Stern is a huge fan of Batman and Adam West's version in particular, so maybe West was on to something...
Graeme Garden once lampshaded this in an interview, and suggested the subtitle be changed to "the template for panel games".
Even certain formats of radio end up being so influential that the novelty of it has completely disappeared. Back in the Fifties, the idea of a radio station running like a jukebox was revolutionary, leading to Top 40 stations popping up all over the United States, and pirate stations appearing in Western Europe when official broadcasters refused to run the format. Now, the format is just a tried-and-tested money maker, and pirate radio is nearly forgotten.