A mediocre engineer is worth on the order of a million bucks a year to one of these big companies... one engineer can create a reasonably large amount of 'capital' - that doesn't make it cheap.

Yeah, you could build that capital for yourself rather than for a big company, if you wanted to; that doesn't mean it wasn't expensive.

That, and I think that big successful projects take a lot more than just someone who can build a decent website. Take friendster... one of my favorite examples 'cause it was one of the real-world cases of a company dying due to insufficient resources being put into systems administration and scaling. They were in the right place, at the right time, with the right product to become what facebook is now; they got traction, but due to performance and reliability issues, they ended up leaving an opening for Facebook to come in and eat their lunch.

And even getting to the point where facebook was is really hard.

I mean, it happens; Craigslist is a famous example, but usually you need more than one engineer worth of capital to build one of these things, and you need more than just engineers.