Given the number of asteroids in the asteroid belt in our own solar system, not to mention the sheer size of some of them, I would say that none of us would have to worry about how the planet would have evolved. It's more likely all life would have been destroyed eons ago.
Hell, living outside the belt is scary enough as it is. Take for example this
this video of a
mile wide asteroid that passed by our little planet on the 6th of this month. If that thing hits our planet, it's all over kids, ... for all of us.
BTW, if anyone is interested, when the full moon rises on Monday evening, March 14th, you might notice something odd; a pale shadow darkening the moon's southern hemisphere. That is the shadow of Earth, and if you can see it, you've spotted a penumbral lunar eclipse.
Penumbral lunar eclipses are not as dramatic as total lunar eclipses. During a total eclipse, the moon penetrates the dark-red core of Earth's shadow; during a penumbral eclipse, the moon is merely in the outskirts. Even so, penumbral eclipses are fun to observe.