The simple explanation does not factor in economies of scale. You might make a good wage working for someone else because they have some kind of market advantage. Would 100 mini-Googles that were 1/100th the size of Google make as much money? No, because their advantage (at least in selling ads) has to do with the fact that they have such a high percentage of the inventory.

I'm not saying some hackers can't make more than their salary's worth by going alone, but the argument is way too simplified to account for the real world.