If I was to make a list of the best tv series I've ever seen the latest entry on it would probably be Angels In America. That's from 2003. I honestly can't think of a single TV show I'd consider truly great after that. Even the list of just good ones would be pretty short. Budgets may be bigger, but that's it, and that doesn't really mean anything.
The vast majority of older TV shows were episodic, which I find, with a few notable exceptions, a waste of time, since they were complete slaves to sindication and had no guarantees of which episodes would be aired when and in which order. Naturally this resulted in shows with no overarching plot, or only a shadow of one, where any changes to the status quo, or character arcs, would be reset by the end of the episode. Most episodes were, by necessity, meaningless in the long run, because the writers couldn't count on viewers having seen it so they could build upon it in future episodes. Only the season finale, perhaps, was allowed to have consequences. With few shows escaping this fate.
Then came The Sopranos in the late 90s. The trend continued with shows like The Wire in the mid 00s. But it only became truly mainstream with the advent of streaming, which finally allowed creators to make whatever stories they wanted, safe in the knowledge that any new viewers can start from the beginning, soon catch up with the show, and know everything they need to know. If you want the old episodic style, that's still what most of network TV is, and you can binge on it on streaming services like everything else, but finally there's a place for bigger and more complex stories as well.
As for great TV shows? There's so much stuff out there now that I don't think I could ever check all of it out. Considering all the shows that have come out, or are airing right now, including, but not limited to, all these shows that I either loved or really want to watch but there's never any time to:
Breaking Bad. The Wire. Broadchurch. The Handmaid's Tale. Game of Thrones. Review. The Leftovers. Crazy Ex-Girlfriend. Bojack Horseman. Legion. Fargo. Orange is the New Black. Black Mirror. True Detective. Band of Brothers. Westworld. Arrested Development. Gravity Falls. Rome. It's Always Sunny In Philadelphia. Mozart in the Jungle. Transparent. The Strain. The Americans. The Killing. The Tick. The Knick. Peaky Blinders. Boardwalk Empire. American Gods. Hannibal. Pushing Daisies. Deadwood. The Crown. Downton Abbey. Taboo. Flight of the Conchords. The IT Crowd. Garth Marenghi's Darkplace. Halt and Catch Fire. Community. Atlanta. Master of None. Mad Men. Top of the Lake. Mr. Robot.
I'm sure there are others out there that I haven't even heard of yet.
If you can't find a single great show in 15 years of television, then you either don't know where to look, or the issue is with you and not with TV.