I will agree with that in certain cases such as Apple or Google, but the startup world isn't really that way.
If you're working for a startup and just think of yourself as an employee you're doing it wrong. You should think of yourself as an investor, not an employee, because you very likely are in every sense of the word.
This is where the friend thing comes in. You're not building friends at company X, you're meeting other people who happen to be investing in the same thing you do. I've kept great friends from previous companies I've worked at who understand that you're an investor and you must look at the company as an investment and be able to walk away if you don't like where it's going.
It does keep you working 60 hours a week, sure, but that's your investment for the shares your received in your offer letter. You stand to make a large amount of money without any capital put in. Regular 40 hour a week employees never get those shares, so obviously they shouldn't put in 60 hours a week to make the CEO a few extra bucks (however there's a caveat here when it comes to bonuses, and i'd argue THATs the return on investment for google employees).
A clearer example of a difference here is that I've seen developers walk away after 5 months at a job. In a regular employee universe that would be career suicide. Because this is the startup world, you only have to say "I didn't like the direction the company was going..." to other potential employers and so long as you're competent they totally get what you mean, because obviously many startups fail and if you see true disaster coming you would be crazy not to bail.
Often times it's actually these "employee" types that kill the startup. They just ride the funding into however many rounds they can until the ship crashes, then find a new place and continue the dragging.
Sorry for the wall of text, but I came here from a place where the "employee" mentality is king (40 years x 40 hours a week x 401k = retire), because it's the most common thing in America and it took me a very long time to get this (I'm an investor, not an employee). There's also the other factors like most people here REALLY enjoy their jobs and have been doing this on their own time for 60 hours a week already, so doing it for a paycheck is just a really cool side effect.