Most GOOD shows start out with a great storyline, the writers and producers seem to do a lot of research to ensure they get details right.. after about 3 seasons they get lazy, and then they turn into evening soaps..
One of my favorite shows - which for some reason I don't really enjoy much in reruns - Babylon 5 - was originally pitched as a five year story arc.
It was a novel idea at the time - he had the whole story mapped out and provisions in the event he would lose an actor or a season would be cut short. He even demonstrated that at the end, the station would be destroyed (which it is - but intentionally, due to a lack of need). He was clear - after five years - the story would END.
Buffy was the first show I can remember having season long arcs - however, they grew tiresome because they always followed the pattern of - there's a Big Bad this season that needs defeating, everything builds up to it - big battle last episode - lather, rinse, repeat.
Some shows I do tire of because the premise gets more - weird over time. "Blindspot" for example - a mysterious woman with no memory covered in tattoos which are clues to crimes - usually cracked just when they're going to happen. Well, she's regained her memory, the tattoos are dated and they caught the big bad - so they're onto MORE stuff. I like "The Blacklist" - but the 'mystery' about just who the hell Raymond Reddington IS, is wearing out my patience.
And some of the ones I watch - sometimes I know I am only pretending to know what the hell is going on, because the plots are just too complex. Other shows have such a huge ensemble cast, that I really can't get into the storylines behind each of their characters from week to week. If I am watching, say, S.W.A.T. - I don't want episode after episode focusing mainly on someone they usually ignore most of the time. I don't care.
One or two - I quit watching because - the storylines seemed like they were PREACHING something to me. I watched "Supergirl" for about a season until they kept preaching by equating prejudice against aliens as racism, and the stories that went with it. And I thought - hell, if I lived in a world where every other month, some world ending event caused by aliens was happening, I'd feel that way too.
So - I don't know. I actually watched very little television until about twenty years ago. Now I find myself slogging through a show and thinking - why do I watch this? I can't even remember if I saw this one before, because nothing is happening.
