I think that a small number of talented people that will work themselves to death will be much more effective than a large group willing to work reasonable hours.
The cynic in me wonders if the attempt to turn overwork into a virtue is just to keep people busy enough that they don't stop to wonder what it's all for in the end. Somehow everyone seems to have forgotten that the economy should exist to serve people, not people serving the economy.
Not claiming this is necessarily effective.
It does show in the products. Great products like "Stripe" start out wonderful but in time slowly move away from that initial greatness into products that slowly get worse and the company lives on in a shadow of what they once were.
But yeah, if all you are trying to do is build out Facebook before some other social network gets there maybe it makes sense to pull 100 hour weeks.