There is another thing behind the Miami "Heat's" troubles. "Heat" management recognized it early on. We don't have The Man in the Middle to block, deflect, and deter shots. The cognoscenti were talking up Steven Adams. Of course we had such a player, his name was Hassan Whiteside, but we don't now and teams, at least the two New York teams recognized and exploited this systemic weakness to positionless basketball. Brooklyn scored more points in the five feet around the basket than any "Heat" opponent had in like five years. The "Knicks" scored even more. When you require your nominal center, now Meyers Leonard, to be able to shoot threes, and encourage him to be out from under the basket then, well, there's no one under the basket. When your specs for a big  man include being able to bring the ball up the floor like a point guard, as I saw Bam Adebayo do with my very own eyes, then, repeat, rinse. For positionless basketball to work, you have to do more than get rid of the nominal positions, you still have to have players who can occupy the "spaces", is that a better word?, the spaces and the roles that each of the five nominal players occupied and performed. If, that is, you want your nominal center sometimes to be 23' 9" from the basket, and bringing the ball up and being a deft passer then your nominal guards and forwards have got to be able to block, deflect, and deter shots and I don't know how you do that in a sport with the object of attention 10' off the ground and only 18" in diameter. Vertical distance, height for humans, is what makes basketball unique in all of sport.