But those shows are the rare exceptions

I would say that good shows are still a rare exception. There were a few great shows in a sea of slop then and a few great shows in a sea of slop now with the biggest difference being that the sea of slop is significantly more vast now. The changes in the medium from old school TV to streaming sites has allowed for a little more of a blurring of the line between movies and TV shows in that prestige TV is higher budget and does take longer to produce, closer to how only movies used to be produced, and it's fine that there are more shows with higher production value and longer wait times between seasons, but that doesn't mean that TV is great now and was bad in the past.