I did complain to my immediate boss, and then when I became a manager, I went to HR fought to make the pay more equitable. Not a whole lot happened, as far as I can tell.

To be fair to them, it's not quite so easy though. You can bring underpaid people up to "fair", but you can't really bring overpaid people down, so you still wind up with some unfair (imo) compensation going around.

Incidentally, the last time I got a raise was when I became a manager and became more aware of the exact compensation numbers for the rest of my team. My plan for the next time I get a raise was to ask them to give it to some of my underpaid team members instead, but I'm leaving this company soon, so I won't be able to see if that strategy would work or not.