We’d get hit a lot more if the solar system wasn’t just right. Wonder how that happened.
During the early days of the solar system, asteroid collisions with planets were fairly common. But the asteroids with orbits that crossed planetary orbits where cleared out by collisions, just as one might expect, purely by chance, over billions of years, with very few survivors. The ones we see these days are mostly visitors from the Oort Cloud, whose orbits were perturbed by encounters with other Oort Cloud objects.