I think the moral of that story is not work life balance. It's that you should work crazy, just don't forget to take a break when you're stuck.

For example, I worked all day today (true story), trying to figure out some algorithm. I got stuck. So I took a walk. And it just came to me while I was taking the walk. Now I'm back and am back to work and it's super productive.

If I worked like 3 hours and then went out to meet friends, have dinner, go watch some musical, and came back. I literally wouldn't have had time to even get to this point.

Back to Archimedes, "The breakthrough came" only because he put his time in, and it just synthesized in his brain when he finally took a break. If Archimedes was a "40 hour work week" guy, he probably wouldn't have got to that state.