Because looting gold from giant rats in the city sewer [and everybody's gotta eat] and saving the kingdom by searching for the Grail are all just stuff you do because it gets ya the tavern Elf chick and a +3 bastard sword to boot. It's all equal as long as you go up in level, right. One achievement is as good as the next. C'est la vie.)
You're saying that like it's a bad thing. AFAICT your particular cultural perspective does not value survival, sex, or excellence in warfare (you obviously don't worship a goddess of sex or warfare, but your PCs might). That's cool - but if you wanted to define "heroic" in more direct terms (other than assuming that comments about "elf chick" would somehow tell us what you must think we already know) I think you'd have a tough time coming up with something universal and appropriate to all genres of fantasy (arguable if that would even be a goal).
Plus what mechanical impact *would* you suggest that moral actions (what you mean by 'heroic' AFAICT) have on the game? If you start handing out bonuses for "heroic" deeds then it turns into the situation that you criticise. In fact, I'm with some of the other folks (AFAICT) in thinking that some specifics relevant to, say, a section of the PHB might help in seeing how you would turn your criticisms into something more actionable.
I'm sympathetic with some flavor of what you're saying. The newer rulebooks do seem heavy on the development of mechanics and light on the development of setting. But from what I've seen so far, most setting information is pretty superficial, and at best a rehash of older material. Ultimately I'd rather them just concentrate on mechanics. This leaves the context, morality, etc. up to the DMs, I don't think that stuff is appropriately done in the rules but my mind could be changed if you would be more specific.