Re: Why do they call the five second back-to-basket rule the "Charles Barkley Rule"?
And you could double the post with the old rules, it was just more difficult. The defender had to wait until the pass to the post was made before he could double, which made not only doubling harder, but recovering from the double insanely more difficult.
These days, you can double a player without the ball, which makes doubling the post easier, and more important, makes recovering from the double much easier. That's why teams like the Heat can play great half court defense without any good post defenders.