So today this could be done by 2 founders without bosses? (the topic of this thread)

Eventually, yes.

For example right now a duo are preparing to do a manned space flight, which would have been unthinkable 30 years ago.

http://copenhagensuborbitals.com/

http://copenhagensuborbitals.com/personel.php

Me: This works with 2 people. You: Yes, look, here they do it with 22 people.

2 of them are described as "Lead" which is contrary to the point you want to make: "You Weren't Meant to Have a Boss."

Additionally the problem of putting someone in space is different from putting someone on the moon and back again.

like matt said, I think eventually yes. It seems silly to us now, just as it seemed silly back a couple hundred years ago that you can run a farm with just a handful of people and even produce more food.

But when you have many tools and building blocks , the problem doesn't require many intelligent decisions anymore , and isn't "big" by the definition given by the parent thread.