I can provide a personal perspective of this year's NBA playoffs, since I watched the games or part of the games when possible. Over the past ten years or so, I've paid more notice to the NBA because it's a sport that's consistently broadcast throughout the places I've lived while overseas. As an overall product, the NBA's in pretty good shape, but there was a number of factors that contributed to poor ratings this season.
It was a disorientating experience this year-I'm not used to watching the games on weekday afternoons and without the true arena experience, things felt off from the start. The long break brought on by COVID-19 didn't help-when they came back to the bubble, I was confused by the regular season games tacked on before the playoffs started and it caused me to take a bit of time to get into the playoffs.
The NBA playoffs have also traditionally held a place on the calendar and TV schedule that felt much different to me this year. Basketball ending in early summer feels natural and without the competition from other sports on the calendar.
Also affecting this year's product was the elimination of marquee teams/players earlier than expected-Milwaukee and the Clippers, and the teams that replaced them are compelling, but not yet household names for casual fans.
Finally, when the Finals began with a blowout win by the Lakers and injuries to two of Miami's starters that looked like it could keep them out of the playoffs, well, that certainly didn't help matters. And again, as valiant an effort that was put forth by Jimmy Butler and his Heat teammates, they are not headliners. Not only did the likes of Giannis A., Kawhi Leonard, James Harden, Russell Westbrook, Chris Paul, and Damian Lillard leave the playoffs early, but other superstars like Steph Curry, Kevin Durant, Kyrie Irving, Klay Thompson weren't around at all. There was a definite lack of star power, outside of the Lakers, this postseason.