I'd argue the opposite to be honest. The NBA is better than it has ever been. Individual scoring is harder to come by because of all the quasi-zone teams are playing (Kobe has mentioned this as well), but league wide scoring is up because league wide talent, coaching, and pace is at a never before seen level. I didn't watch basketball in the 80s but 90s basketball was terrible. The 90s were a watered down, out of shape league because they added 6 teams in 10 years and you had guys on championship teams that were out of the league a few years later. The pace of play came to a screeching halt because the philosophy was that clock management won you games. Teams used the entirety of the shot clock, allowing defenses to set up, yet still scored more points in the paint than today because of the awful illegal defense rules. The 90s had little ball movement and more ugly iso ball than I've ever seen, the league probably would have crumbled if it weren't for MJ.
The league has changed so much. There is so much talent and it's much more complex with all the scouting, preparation, and game-planning involved. Teams shoot more 3s and play at ridiculous paces, that adds to why there is so much scoring. But with where international ball is, as well as the d-league, you really won't make it to the NBA if you dont play defense. Even guys like Harden, Melo, Love, etc aren't bad man defenders. They get lost through all the switching and zones they have to play, which good offenses make sure to take advantage of.