Yep, good points on teamwork.

I think it's inefficient to try and change corporate culture from the bottom up

The apparent alternative, top-down, doesn't fare much better - I speak from some experience.

Culture change in general is very hard to bring about, because what we think of as "culture" tends to be precisely that which people do without thinking about why. To even describe cultural aspects often requires talking to an outsider: "Sorry about that, I should have explained that we don't greet people with handshakes here."