The NBA has moved to a 3+D league with a preference for its non core starters to fit into that mold at the 2,3 and 4 positions -- but that is often the only above average skill of such players. They can't create that well for themselves. Teams have reacted by improving the 3 point defence, but this has really spread the floor.
Star players can now create much more in the 2 point space, and teams are willing to let them for now, if it stops the opponents from taking 3%'s at a 36%+ clip. So it's easier than prior years to get an efficient 2 point shot right now, but less players on each team have the skill to do so. So the usage level for some players right now like Westbrook, Lillard, Davis, Derozan is incredibly high, and they garner numbers that are ridiculous. As teams have less playmakers they have the ball in their hand more often (more assists), and without a traditional 4, a guard will get much more rebounds as well.
The NBA became a 3 point trigger happy league because analytically it made sense. Teams adjusted and I think the 3 point shots may have peaked after a many year climb. It will be interesting to see if teams counter adjust to players who are attacking the spread.