Superman regularly gets a lot of shit for maintaining a 'secret' identity that amounts to wearing glasses, combing his hair differently, and stooping a bit, but I'm really not convinced Batman's cover is really any better.
Seriously, we're looking for someone who:
- Lives within an easy drive of Gotham city centre.
- Can treat millions of dollars not merely as disposable income, but so trivially that he doesn't even need to consider throwing it away.
- Has a sizeable period in his bio where he was off the grid - the time he was away learning all those martial arts he knows.
- Regularly appears to be suffering significant physical injuries, perhaps from some sort of extreme sports.
There aren't all that many people worldwide who fit any of those criteria. The list of people who fit them all has one entry on it.
The only reason Batman isn't unmasked immediately is that the police in Gotham fall into one of two camps: those corrupt to the point of uselessness, and those honest coppers who don't want Batman unmasked because he's an ally (that is, Jim Gordon).