One "side" insists that they won't come back, but it almost seems as if they forgot that some of us left 3E and yet others skipped it entirely.
I agree that this point is often missed. I'm an example of someone who had no interest in playing 3E, and who came back to D&D because 4e offered something different.
Now the impact on WotC's bottom line isn't as great as that comment might suggest, because altough I didn't play 3E I still bought a number of 3E modules and supplements to get ideas, scenarios, etc for the game I was running (Rolemaster - which doesn't have quite the publishing schedule that WotC does).
But still, my collection of WotC purchases has increased at a greater rate in the 4e era, and I also have several players who have DDI subscriptons, 4e rulebooks etc who weren't buying those things when I was running Rolemaster for them.
The +1 per 2 levels may very well be gamist, but I do see valid ways to describe it in a simulationist manner.
Here I think there is some confusion or terminological cross-purposes between you and [MENTION=6685059]LurkAway[/MENTION].
By "simulationist" mechanics, I'm pretty sure that what LurkAway means is what the Forge calls "purist-for-system simulationism" - that is, mechanics that model the internal causal processes of the gameworld, therefore exhibiting that causal logic in play.
Although your description of why an Epic wizard has a +15 to break down doors makes perfect sense, and is how I understand what is going on in the gameworld, it is not really simulationist in the purist-for-system sense. The mechanics aren't exhibiting ingame causal logic. Indeed, the very same mechanic - a uniform level bonus to skill checks - represents something different for each of the wizard's skills (with Arcana, for instance, it's not the subtle use of enhancement magic but rather greater learning and proficiency in the magical arts) and something different for different PCs (for a fighter, the +15 to athletics checks means something different from what it means for the wizard).
What your description of the +15 bonus
does do is show that there is no trouble, in adjudicating 4e, in explaining what is happening in the fiction that is reflect by the action resolution mechanics. The game is therefore not "gamist" in the pejorative sense used by some ENworlders - meaning roughly, I think, that the mechanical outcomes have no fictional meaning. (This use of "gamist", it might be added, has nothing to do with the way the word is used by The Forge.)