In the 60s to 70s, the US had 3 networks (ABC, NBC, and CBS), few shows, low budgets even for hit shows (think of Gilligan's Island and Brady Brunch), and massively greater viewership than today[1]. And the average American viewer watched 4.5 hours of TV per day and knew the name of every prime time show on TV.
Today, every point above is reversed: hundreds of channels, hundreds of shows, something like one-tenth the viewership per show[1], and people watch much less TV.
To give one example of budgets, an entire episode of Star Trek cost about the same as just the voices on a Simpsons episode. (Star Trek cost $185,000 per episode, or $2.2M in today's dollars; the 6 main voices actors of The Simpsons were collectively getting $2.4M per episode but cut to $1.8M a couple years ago.)
The only conclusion is that TV in the 60s and 70s was obscenely profitable and TV today is a marginal or money-losing business and covertly subsidized by other parts of the company's business.
[1] The final episode of MASH had 125 million viewers. https://en.wikipedia.org/wiki/M*A*S*H_%28TV_series%29
The final episode of Breaking Bad had just 10 million. https://en.wikipedia.org/wiki/Breaking_Bad#Viewership