It's not just nostalgia. Despite the scores of made for TV series being made, the older ones were better. MUCH BETTER.
Chances are if you turn your TV on, you will watch one of several formulas: situation comedy (shit Comms), medical dramas or police procedurals. There are a few variations but not very many. It's what Hollywood knows how to do and they make them like an assembly line of Toyotas.
It doesn't take too long to notice that there are really only about fifty themes and they make them over and over again.
You can blame writers unions. There might be something to that.
You can blame the studios. There's definitely something to that.
Blame the viewer for not turning them off. Blame the advertisers for branding their mediocrity.
There is a REAL difference between golden age TV and the shit that is being excreted today. The difference is in the writing. The writers for golden age TV were not TV writers. They were writers of plays, short stories and novels. They had writing experience outside of the movie and television echo chamber.
Should you look these up and watch a few episodes here are a few things to look for. In Perry Mason, look at the way the episodes are structured. The writers used the traditional 5 act structure. It's not brilliant. It just the same thing that's been working since Aristotle's Poetics.
If you look at the Twilight Zone or the Outer Limits, notice that these are plays derived from short stories. Also notice that they were originally written by some pretty big name sci-fi authors.
What we're getting now is...
Modern telecommunications technology can deliver hundreds of independent channels. There's just no excuse for there being nothing worth watching on any of them.
Things are happening. Billion dollar productions are falling on their face. It will take a few of them going broke on their formulas.
It will be the innovators that survive and thrive. The innovation that can most easily and most likely turn things around is looking to the traditional elements of drama and apply good writing.
That will work and has worked every time it's been tried.