I naively assume that the only way to succeed big in wall street is to rely on insider information. The rules against insider trading only hurt those trading at home believing the playing field is level. But I don't know how it really works.
In a perfectly efficient market with perfect information there's no profit to be made. So to make money you either have to be more efficient - either by market-making where you do millions of small trades, or the kind of value investing where you just buy what other people are selling and vice versa and hold them for a while - or you have better information. (Which doesn't have to mean inside information. It's certainly possible to make a living out of good old-fashioned detective work based on public information - recent clever tricks have been e.g. tracking the tail numbers of CEOs' private planes to know when they're on holiday and/or negotiating a merger).