There's a million reasons why earth is habitable and nothing else is. In fact in all that we have been able to observe the Earth is the only place with the exact perfect conditions to support life. Change any of those things a little bit and the earth is dead. So it's not just moons.

Jupiter has a lot of moons because Jupiter is huge and that gravity captures a lot of rocks flying through space. It's also incredibly radioactive and any living thing near Jupiter would be killed pretty quickly from radiation.