PROTIP: Humans aren't a Hivemind, and we all don't get along. Even if we all didn't play Halo, and focused on something else. We wouldn't get very far, because we'd all be doing independent research, on a smaller scale.
I mean really, 64,000 years? With those hours combined we should've been able to think of another way of space travel or find a cure for cancer or something. (well given the fact that most of the players are kids I can see how they'd just use their time for some other sort of entertainment, but the adult hours spent in there surely must make up a few thousand years.)
How many man-hours have been spent watching NFL in the past 18 months? And how many man-hours thrown away on American Idol or Days of Our Lives? Perhaps those hours should've been spent healing the sick and feeding the hungry too, but us humans are stubbornly insistant on having our down time.