I see one of the arguments in favour of Batman is that he is a testament to the upper limits of human ability and training. If that were all he was, then fine, but it's not, is it? I mean, yes, he's well-trained and all that, but also a very large part of being Batman is the gadgets. Can Bruce Wayne even be Batman without armour, a grappling hook and bat-shaped boomerangs, not to mention a sweet ride? Take away all the gadgets and Batman is just Gravel-Voiced Punching Guy. He might be good at that, but it's not everything we think of as Batman.
Mokalus of Borg
PS - I'm sure, in his long history, there has been an exploration of what non-billionaire Batman would look like.
PPS - I'm sure it felt like there was something missing.