Working long hours being single helps because your time is yours. Once you have a family your time isn't all yours anymore. Most of the Mac team, we were in our mid-20's, most of us were single, and we were able to essentially devote our lives to it.
I published on the web about 60 anecdotes about the development of the Mac in time for the Mac's 20th birthday in 2004. And that led to a book.