"Some American shows that start off weak can grow their beard when the show would have long been over in the UK."

That's interesting, since here in the UK we take the same view of US television: ie we think that US networks are overly-competitive and will axe a show mid-season without giving it a chance to "bed in" whilst many British shows which "failed" on their first season (or "series" as we usually say over here) are often given a second chance and go on to become huge successes. This is what famously happened with "Blackadder" but also applies to "Men Behaving Badly" and other shows.

Last Of The Summer Wine is listed as averting this trope, but since it has only had 289 episodes over 28 series, it's averaging <11 episodes per series. Which fits squarely in this trope (there may be specific series which avert it, but not the entirety of the show).

Does it seem to anybody else that this page might benefit from a short list of counter examples, ie: American Long-runners