In the last 40 years, the diversity of channels and then the internet actually fragmented the audience for content. In the 60's, 70's and 80's, everyone watched three networks, CBS, NBC and ABC. The ratings for those shows were incredible by today's standards, even though a lot of those shows sucked. Then, as cable channels proliferated, a few people managed to push out syndicated original content like the Star Trek franchise or Baywatch on local channels and places like USA Network. Content for kids started showing up outside the major networks, and ringing up pretty good numbers for non-network shows.
Then HBO started making original content. The Sopranos changed everything. There was NO WAY that show could go on broadcast television, and while its audience numbers were big, they were nothing like the broadcast audiences for even mediocre shows. But it simultaneously changed both television and the movie industry forever. All the cable channels started developing original content, and the networks re-thought what qualified as a hit. Movie producers realized that cable might be a better platform for content targeting people over 30, and started churning out the best television in history. Most importantly, no one needed to produce weak, vanilla content that had to appeal/not offend 20 million people. Artists could make interesting, niche content.
The West Wing would have definitely been cancelled in 2001 or 2002 if not for the Sopranos. The West Wing was expensive to make and it was generally not a Top 20 show. But it was prestige television and NBC was light on that kind of programming at the time. Then AMC, which was hanging by a thread, produced Mad Men and Breaking Bad, which saved the network and launched AMC into this weird hybrid of niche, prestige television and horror. Showtime produced some hits like Shameless and Dexter. FX, TNT and USA all got into the game, along with a lot of the niche channels like Nickelodeon.
Not everyone wanted to watch award winning TV. MTV kicked off the dramality genre, which took over channels like Bravo and TLC. I am guessing that the founders of Bravo are appalled (if they are still alive) that their channel, which was originally targeted at the Lincoln Center set, is now primarily broadcasting middle-aged women wearing $5,000 outfits scream nonsense at each other in front of a drunk Andy Cohen.
Netflix was initially a renter of movies, but transitioned into an incredibly profitable movie and TV studio, churning out mediocre content at good prices that keep its subscribers just happy enough to pay the next month's bill. The major networks and studios all raced to get in the game, with Disney/Hulu (ABC), Peacock (NBC) and Paramount (CBS) all trying to keep up with changes they fought for years. Being a reseller (like a network or certainly a cable provider) is basically a dead business model. The content producers will own the future because they don't need much help from the networks, and they need none from cable.
So where is sports? Kind of like TV was when the Sopranos first went on the air. People are realizing that they can watch what they want, not what ESPN decides they should see. I have some ideas about what might happen, but the only thing I am 100% certain of is that sports broadcasting will look hugely different in 10 years.