Good TV Shows gets cancelled prematurely, while Boring TV Shows run on for too long.

Counterpoint:
Good shows remain good because they were cancelled before they got boring.
Boring shows were good shows that got drug out way too long.
- Lower standards are easier to maintain. If a show appeals to viewers with low expectations, it can retain those viewers for longer. Example: The Big Bang Theory.
  
  With shows like The Big bang theory I usually just put them on when I'm cleaning or cooking so I have noise in the background.
  It's not captivating enough to make me sit down and watch it but it's not off-putting enough that I can't stand listening to it in the background.
  Honestly that's probably where a non-Insignificant amount of viewer retention comes from in low effort shows.
- Or were mediocre to begin with. Thats why they performed good for a wide viewer base that does not care about "good" as long as it entertains enough to be distracting.
  
  That's just misanthropy though. People have their own idea of good which may not align with yours but nonetheless exists.
  I bet I could dunk on your tastes for hours, it wouldn't mean you "don't care about good", just that I enjoy being mean.
- I also like shows that follow a story arc that has a beginning and an end. A show that comes to a natural end. Bam, done, that was great entertainment, emotions and attachments have been resolved. Happy end or sad, this is it. Moving on.
  Instead they try to retain viewers with dumb (and I really mean dumb) cliffhangers, never committing to actually killing a character so they can bring them back if need be etc. ...
  There are exceptions of course, but not many shows deliver (lasting) quality beyond two seasons.
  
  That's the main reason I stopped streaming all those new shows. They get canceled with some half-open ending, and it feels like a slap in the face.
  Filler-content is somewhat expected when seasons are getting stretched, but without a decent ending I ain't watching no more.

Art is always a risk. Under our current system it's more profitable to minimize that risk. Thus you get the boring and predictable

Anything longer than 5 seasons and they're just milking it.
- Unless the arc is pre-written even if you bulk it out with fun one shots like Star trek
- Better call Saul and breaking bad tho

Boring TV shows tend to make money. Daytime TV for pensioners. It's boring as hell but you're at work, or streaming content, or on the tiktoks doing virals for dings.
Broadcast TV, where most shows still come from, are not for you. You ever notice just how many procedural cop shows there are?