Valve is one company. Their revenue is... for one company. If three companies competed equally in that space it would be billions / 3.
You get that, right?
Also, integrated graphics are still way below what the PS3 and Xbox can do, and yes, the PC is unpopular. Does that mean it doesn't generate funds? Of course not. But you're so quick to say that the flaw of consoles is the platform and that by making PC games they'd solve it. This ignores that a huge chunk of games are ON the PC now, anyway. It ignores that the problem may be the content, not the platform. And it ignores that the public overwhelmingly wants something they don't need to tinker with, hence Steambox.