I think one of the major reason is that the league (Stern) in it's "wisdom" decided that NBA had to have more flash, more driving, more perimeter play (so by definition more highlight plays from guys like Kobe, Wade, Iverson, Parker, etc.) to market the game as an OFFENSIVE game. Stern realized that if NBA was going to become more popular, it couldn't have teams pounding the ball into the middle/paint and have 75-74 scores. So they ins uted bunch of rules (3 second rule in the paint, no hand-checking in the perimeter, let the Bigs pound each other in the paint without calling fouls, etc.) that FAVORED the flashy perimeter players at the expense of the traditional Bigs/Centers who played in the paint.
I have seen Duncan get hacked, pounded, pushed, his jersey being yanked (by Kurt Thomas), held, hooked, tripped, gouged, kneed.....with NO FOULS being called in the past few years. If you even touch a perimeter player little too hard as he is whipping by you, fouls were called constantly.
So obviously given those kind of advantages, it made perfect sense for the game to evolve towards perimeter play since it was so tough to score in the paint when the Bigs were getting pummelled with no calls being made.
Apparently this year, Stern listened to the coaches and has instructed the referee to allow more physical play in the perimeter and LESS physical play in the paint. How that will play itself out as far as re-emergence of post players will be interesting (that;s if there is any post-up players left other than Duncan).
In any case, if the referees are going to call more fouls against the Bigs hammering the other Bigs, then this bodes well for TD who should get more fouls called. I noticed that in his preseason games TD is going to the line lot more per minute (and making them!!) so he could have a great year scoring wise if the refs continue to call fouls more aggressively in the paint.