Ancalagon
Dusty Dragon
I think because 4e and 2nd ed AD&D both aspire to produce stories of fantasy heroes undertaking fantastic adventures (and so are both quite different from classic Gygaxian D&D), but use extremely different methods to get there.
2nd ed AD&D has almost no mechanics to produce this outcome - it has almost no mechanics beyond those found in AD&D (and before that, in OD&D + Supplements). So it relies almost entirely on GM force to produce this outcome - as per, say, [MENTION=6801878]Dorian_Grey[/MENTION]'s example in post 250 upthread, of gifting players with special resources for their PCs.
4e has probably the most intricate mechanics of any version of D&D. The combat mechanics come close to guaranteeing conflicts in which the heroes will struggle, but then - by drawing upon the depth of their resources, which will include the inspiration of the divinely gifted or merely gifted - turn the tide and overcome the odds confronting them. 4e also has mechanics for resolving non-violent conflicts in a similar dynamic way, with a story-like finality of outcome built in (ie the skill challenge mechanics).
The monster build rules, as set out in the default MMs, in conjunction with the PC build and tier system, come close to guaranteeing that a default campaign will unfold "the story of D&D" - starting with kobolds, finishing with Orcus or Demogorgon. And the PC build rules, especially for Paragon Paths and Epic Destinies, also guarantee that the PCs will be invested in the escalating fiction of the campaign - as Knight Commanders, Demigods, Archmages, etc.
Unlike in 2nd ed AD&D, all these outcomes will be generated just by opening the books and pressing the play button - it doesn't need the GM manipulation that 2nd ed AD&D does. It's built into the system, and follows near-automatically from the deployment of that system.
Whether this difference is a positive or negative is something on which opinions differ.
I'll be frank here and note that my experience of 4e is very limited. I started looking at the rules, went NOPE and walked away. Not saying it was not good, but it was clearly not good for me. I dabbled a bit with essentials later on but not much more beyond level 1-2 stuff.
So I had no idea about this "baked in epic hero stuff". I'm going to take your word for it. And I do like this kind of epic heroic stuff! But... should it be baked in the system? What happens if we want to play a bunch of shifty rogue-ish anti-heroes?