If magic items are not so tied to power than wealth is not a problem anymore, in 3rd edition the problem with wealth was only that PCs could use it to buy powerful weapons and armour i.e. large bonus to AC, BAB and stats, but apparently in 4D! power don't come from magic items anymore, (not in such large quantity, at least) and I can't think to nothing else that PCs could buy to break the game balance (I mean what could they do? Buy lands? I wish. Hire an NPC army? Big deal, after a little every single PC allone would be much more powerful than that army).
this if they do it right, of course.