Some stats:
~350 million users[1]
~17Mb download[2]
Lets assume a full 25% is dev tools (I think its likely to be much less), so 4.25Mb per user. That's 1418Tb, or just under 500 3Tb disks. Considering that's spread across 350 million users, I think that's not too much at all, and its probably much less.