The r/NBA frontpage explains why the media only spends time covering a few popular teams in the league. They're just following what fans want.

Every single time a thread gets posted about ratings or why the media's coverage of the league sucks, people always mention that the league only covers the Lakers etc. But just look at the frontpage currently. There were a lot of games played yesterday and if you look at the post game threads for them, people simply did not care. People here don't actually want to follow the other teams other than the smaller segments of fans who watch their own less popular teams.

I don't think ESPN covering the Trail Blazers figuring out how to win games is going to make fans of the game and people on this subreddit talk about the Blazers more for example. It's unfortunate, but reality.