As ever, context is king. There would have been no use flopping or selling contact in the 80's because it would not have created much of a competitive advantage. The refs wouldn't have started to blow the whistle more frequently just because players started flopping left and right, so guys like Lebron and Chris Paul likely wouldn't have bothered with the theatrics at all. Nor would James Harden initiate contact as often as he does with the express purpose of drawing a foul. The refs wouldn't have blown the whistle in his favor with any great frequency in the 80's. But because Lebron and Paul and Harden can create a competitive advantage in today's game by (over)working the refs, they do so.
I don't like it or admire it, but I also don't blame them. The NBA created a "legislative" environment where the referees have far too much to watch on the floor and far too much to manage within the absurdly-paced speed of the game. There are simply too many "calls" for them to make, and the human eye can only process a limited amount of information in real time. So the appearance of contact is often enough to earn the whistle. If the NBA truly wanted to cut down on flopping/selling contact, they would give the referees less to do, not more. They would eliminate the hand check rule and allow the defender greater latitude with respect to incidental contact. Lebron stops writhing on the floor if it no longer serves his interest to do so.
