So what is D&D simulating?
Ultimately this is a pretty abstract question and the answer could be debated for months. (oh wait it has been...)
But, more importantly, imo, is that the question seems to make a fairly decent litmus test (at least for the extremes). People who find 3E/PF to their taste tend to see that question as asking "what are the details? what are the relative important aspects to me?" While people people who express distaste for 3E's approach consistently express the question as a challenge to the idea that D&D has ever simulated anything.
Clearly, for a lot of people out there RPGs have never been about simulation. And they played prior games (pre-4E D&D or other systems altogether) and played them in highly "gamist" manners, whether that term ever occurred to them or not. 4E comes along and plays directly into what they enjoy and they are thrilled.
One problem seems to be that older games could be played in a very "gamist" manner and different groups could be playing the exact same system a mile down the road in a very "simulationist" manner.
3E did gamist just fine. 4E does gamist a hell of a lot better. That is why there is no small number of former 3E players who have made it clear that they will never go back. What used to be "good enough" doesn't cut it any longer.
For people who we would now call "simulationist", the difference is that we already had the hell of a lot better game.
But if you don't accept that anyone else ever experienced "simulation", then that is fine. Time has proven that trying to explain it is wasted energy. It seems you either get it or you don't. But it isn't important. Play what you enjoy and just be aware there are preferences that are quite real and contribute significantly to where the preferences now exist.