You unfairly run together a number of features of playstyles that are actually quite distinct.to some of us "fun" involves a hell of a lot more than the mini battle game portion of experience.
For those of us more interested in the being part of a different kind of world, being engaged in the activity and consequences can be a ton of fun for the player, even if that consequence takes his character out of the action for some period of time. On the other hand, having the world be contrived to never take the player out of activity, regardless of how logic dictates they should be (Hey guys, that medusa just looked at me. I'm feeling slower. And gee, in a few rounds I might even turn to stone. But the good news is this world is built to keep me in play and I get to keep going and even have really good odds of shaking this whole thing off on my own anyway) is the exact opposite of fun.
To begin: You appear to equate a particular mechanical preference - for metagame-heavy plot-protection mechanics rather than simulationist/immersion mechanics - with a particular flavour preference - for combat-heavy rather than exploration-heavy play.
But I can't see any necessary connection between the two categories of preference. I'll give examples to explain why.
Some people who like a combat-heavy game also like immersion-encouraging, metagame-free mechanics. You'll find a number of them posting on the RM forum on the ICE boards.
Some people who like a combat-light exploration-heavy game also like metagame-heavy mechanics, in which the mechanics allow the player to choose the stakes for his/her PC. I imagine some of these people play The Dying Earth (light-hearted exploration) or HeroQuest (ultra-serious exploration).
Furthermore, even looking only at those who like combat-heavy play with meta-game heavy mechanics, it's a little rude to imply (as you do) that their play is shallow. The Riddle of Steel fits this description (combat-heavy flavour and meta-game heavy mechanics), and it's self-evidently not a shallow game. There's no reason 4e need by shallow either (though it has more potential for it then TRoS, I imagine, having no obvious analogue to Spiritual Attributes).
And some meta-game free exploration-heavy play can probably be pretty shallow - I've certainly seen some 2nd ed AD&D modules that seem to fit this description.