I'm A Banana
Potassium-Rich
What it is more of an aspect of is the "let's kill everything and have the best PCs for doing that" mentality. When you come down to it, magic items are primarily useful in combat. When the game focuses on that, of course magic items rise in importance.
I'll buy it.
D&D3e was specifically something of a reaction against the 2e (at least) idea of "here's a bonus, but it's REALLY RARE!" or "here's a bonus, but IT MAKES YOU UNPOPULAR!" Problem being that those characters dominated in combat (which was a part of almost everyone's game), and their weakness was sometimes never asserted (because not everyone played games wherein characters had to be popular or who couldn't be rare or special).
So the mythical 3e balance came into play in the known (nearly) universal of the game: combat.
And they left individual DM's to do the whole flavor part of it.
Which has lead, through the influence of the core books, to very little attention paid to that flavor part of it.
To reverse the trend, if indeed we want to, we need influential products that successfully focus on non-combat, that also aren't just for the DM.
Combat is crunchy. Combat is random. Combat is fun, fast-paced, exciting..almost by default. Work needs to be done to make the rest of the game feel and play that way, to make the drama of intrigue as tantamount to the players as the drama of combat.
So far as WotC has been concerned, and they are the most influential, it's been a mixed bag. Eberron's adventures from my hear tell are weak sauce. While books like Heroes of Battle are generally only moderately well recieved. DMGII was in that vien as well, but it was DM-focused, not player-focused.