Who says that's what men worry about more than anything else? I don't worry about it at all. Maybe in a few decades, but now that's the least of my concerns. The fact that I need to get a haircut ranks much higher.
I'll probably just do what my dad has done and not worry much about it. It doesn't seem to run in the family that it's the no-hair-at-all-on-top-of-the-head-but-some-on-the-sides pattern, so it doesn't result in looking like you're 70 when you're 55. It's not quite like kmad's grandpa, but my friends tend to think my dad is about a decade younger than he actually is, even though he hasn't done anything whatsoever to combat natural aging beyond a bit of exercise and the aforementioned hat-while-out-in-the-sun-for-a-long-time, so I think overall the genetics are fairly decent in this regard.
On the other hand, if I do go bald in 5 years I'll probably just look into what facial hair pattern would look complement it well, and call that a day. It's not like it's impossible to look halfway decent if you do go bald early.