I think it's an interesting point, but using Rails doesn't mean you have to structure your business like 37 Signals. I did read Getting Real, but with a grain or two of salt. It had some really good points, but understanding their point and trying to emulate their business structure (as they suggest you should) are different things.

Busting your ass and forming a company with a larger growth potential is still an option. It makes things riskier, but some people are fine with that.

The point of this really should have been that you need to be cognizant of the type company you are creating, realistic about its chances for success and aware that VC funding is only a means to an end.