Can be summed up pretty easily.
1: After the first couple of games, people realized that (despite there being some good games) these were still end of regular season games. The most compelling basketball was following the teams competing for the 8/9 seed, and all four were teams that a lot of people that aren't really into the NBA don't really follow. Also, the scheduling was crazy. There were days that games were on at like 10/11 AM out here on the west.
2: It's been said a bunch of times in here, but networks don't get concerned until key demos start underperforming. They're still doing alright there.
3: Hard Knocks was set up to fail. There wasn't much promo, they're covering two teams without much buzz, and without preseason games, coverage of training camp is more tedious than usual. And having watched the first episode, shyt is gonna be trash this year. They had little to nothing to work with for an hour long show.
4: News is going to be crushing everything in just straight up viewers until January, at minimum. Election years are normally great for cable news networks, and this election will be the title holder for fukkery for the forseeable future. On top of that, the pandemic is still feeding them tons of viewers.
Realistically speaking, none of these networks should be sweating this all that much, assuming those in positions to be concerned have been paying attention.