And I think you are underestimating how hostile space is to life. Tardigrades can make it, to some extent, for a limited amount of time. Doesn't mean all life is invulnerable to near absolute zero temperature and constant radiation. Add to that the temperatures a meteor reaches when they crash through an atmosphere, granted without much an atmosphere there isn't much to generate friction. Yet the impact would still be devastating.

It's certain we still don't have enough data to make any conclusions about how easy it's for life to spread. I'd wager it's less than expected yet in our galaxy, my guess would be that either hundreds or dozens of planets/moons contain life. Depends on the statistical distribution of the occurrence of life.