Also stuff like this only works in simulations, the actual trading fees make this totally unpractical.
ETA: That's not to say this is a good book. It's not. I'd recommend Vidyamurthy's Pairs Trading and Harris's Trading and Exchanges, but there really aren't many good books on this style of trading--anyone who knows how to do it well has no incentive to write a book on it.
The rest of us can go pound sand though.
The biggest players in this game are not massive NYC investment banks.
But, you're right in that there are a bunch of small hedge funds that are operating in this market, too. Still doesn't make it very accessible for those of us without a boatload of money up front to get access.
GS isn't even top-5 on NASDAQ.
Professional trading was never cheap. The barrier to entry for becoming a high-frequency trading firm is much, much lower than becoming a NYSE specialist was a decade ago. You could co-locate there for a few million dollars, which is small money all things considered.