Yeah, I'm not a big fan of the 1 minute * 300 million argument because we fritter enough time away already (TV, internet, waiting in line, chewing too slowly, hitting snooze, etc.). A minute here or there will invariably be sucked up somewhere else.

I used to work at a large, very large, software company. I learned not to buy the argument of ("Hey, design this right and you'll save 1 minute on 450 million machines") as a motivating factor. You just don't notice small things enough, and there are a million small things every day. (Did you notice the new wide-mouth soda cans? They do save you time gulping. But would you be satisfied being their inventor?).

Personally, I'd prefer to have a large impact on a few people and grow from there. But that's just me.