the x-files, watched it when nobody heard of it, then everybody watched it, i gave up,so im a trendsetter(lol) not a follower
I actually enjoyed the earlier seasons a lot. When they (sort of) replaced both Mulder and Scully... that was a bit much. The longer the series got in the tooth, the twister the teeth became... I really enjoy Gillian Anderson as an actor and she and David Duchovny played well off each other, though the drama far outlived the fun in the series for me. i only watched part of the last return, short though it was. Sometimes twisty and turny is fun, sometimes, it just makes you dizzy. I don't think it jumped the shark, so much as rode the sharks off into space... I loved the lone gunmen. Their trajectory broke my heart. Other than Stargate SG-1 and MASH and some of the law and order series, i can think of only a handful of shows that went past 10 seasons that were really good, consistent and enjoyable...
I loved Criminal Minds, but the last few seasons were less fun and less imaginative and I have quit following what they brought back as Evolution after the original series ended (and should have stayed dead, IMO)... b/c I can't believe in an 80 year old FBI agent and the rest of the supporting cast are also getting too old to be field agents and the writing is becoming more and more ridiculous. I could maybe buy them as real BAU agents (they mostly do research) but the TV's BAU is a field unit... It feels more like the actors like each other and it's a good job than that it's still a really good show (any enjoyment is from those interactions, more than from any original ideas). It's become more and more FBI fantasy than FBI procedural.... but people have a hard time letting go things they love, even after they're pretty much worn through.
Other than the Law and Order franchises that rotate people in and out as they would in an actual police force and legal offices, and thereby keep it
relatively fresh, most shows really lose focus after 5-7 years. If they keep main cast, the senior cast are often bored and phoning it in and sometimes one person starts to dominate the show so it becomes THEIR series (which gets obnoxious, yes, NCIS, I'm looking at you and your terrible writing)... and if they don't keep the original cast, the loss of core cast, especially if it's most of them, really just guts the show b/c so many shows depend more on the beloved actors than the writing.
One rare show that really thrived after the (so called) core cast left was NYPD Blue... The pretty boys the network insisted on hiring left for their 'great successes' and the dumpy ordinary guy who actually looked like and sounded like a cop... got to have center stage and he was AMAZING as Andy Sipowitz. the credit goes to Dennis Franz (the actor) who was basically a first class character actor who became lead when the 'leading men' went off to try to 'leading man' elsewhere. In a very real way, NYPD blue was two different shows... years 1-6 and then 6-12. The 'everyman' version was far and away the more interesting version.
To come back to the X files... the show had a lot of good supporting characters, but it depended on Mulder and Scully to carry the series. That was both a strength and a fatal weakness. When they weren't available, the back up gang simply weren't able. Robert Patrick (who is very much a 'G man' type) is wrong for the (goofy, funny, but also smart
and weird) Mulder role and his female lead simply was not memorable as a partner (i couldn't even remember the name of the actor who played Reyes until i looked her up). Gillian Anderson is a hard act to follow. I believe her as both physician and FBI agent. I don't even remember Annabelle Gish's back story. Add to that, the chemistry that the replacements did
not have together. I remember not hating them, but I don't remember their time on the series well.