Why Does Our Solar System Not Have Moons?

Rings are moons that have been torn part by tidal forces. And what we're seeing is something transient, that these rings might not last for very long. So they might be there a million years or so, but if you leave the solar system and come back in 500 million you might find that they're not there any more. It reveals to me just how often i assume that science has figured out so many things that are much harder than i apparently understand.