One person I'd pinpoint as contributing a lot to bad TV is Mary Ellis-Bunim. I believe she's the person behind the Real World from MTV back in the day. In particular, her style that has spread to many of the crap shows on TV now is the splicing stock footage between segments or scenes. It's literally just garbage filler that adds up to minutes of a show, seconds at a time.
I hate when bad ideas spread like wildfire.
By the end of the 90s, her formatting tricks for piling on the filler were the norm for the explosion of reality TV that plagued the 2000s and beyond. To add to your point, what worked in tandem to create the sea of cheap, mindlessly digestible reality shows was the TV gods realizing they could conjure up enough of an audience by featuring otherwise faded celebrities into the fold. The Osbournes (which was actually good), Hogan Knows Best, Wahlburgers, Girls Next Door, Real Housewives, Kardashians, etc. One show that stands out as encapsulating the worst of these is - does anybody remember ROCK OF LOVE with Bret Michaels (2007-09)?
Style-over-substance "Rocker Girls" competed weekly via elimination to be Bret's next groupie, fighting drunk with each other and luxuriating in a ton of inappropriate attention and things Bret says to them that would never survive this Me Too era. The 80s Rock culture is played up so much and taken so seriously - tramp stamps, fake chests, black eyeliner, head bands, bad hair, guitars suspended from ceilings - that the total douche factor generates an atmosphere of an ongoing, un-self-conscious parody of itself, unto itself.
I'll admit I watched, but my greater point is that the 90s was the last decade in which TV shows all worked hard to create realities unto themselves, unconcerned with playing off or referencing the rest of TV/Movies. The 2000s is when TV realized it could get away with living off the past, passing off mere celebrity as bankable substance, fueling storylines or conflict based on obsessive references to Pop Culture, and leveraging nostalgia in place of risking creativity.
