I have read previously (don't know if it's still true) but a sport generally increases in interest when there is a 'super team' that everyone else is trying to knock off. Parity seems to be the dampener of interest. When the Yankees and Dodgers are good, MLB tends to draw better. In the NFL, everyone wants to dethrone the Patriots. LeBron in the East. MJ in the Bulls run. Tiger in golf.
I do agree, though, that the past 2 years in the NBA the regular season has seemed like a dress rehearsal for the Warriors and Cavs to play in the finals. Sort of the same way I feel about CBB regular season - it's pretty obvious really early in the season which teams will be the true contenders for the NCAA crown. At UK, for instance, it's almost a given that if they win 20 games, they'll be in the tourney. Makes the regular season pretty meaningless, imo.