Lagrange Points

No.11214615 ViewReplyOriginalReport
Points L4 and L5 are stable. So why haven't moons developed at these points?
We know for example in the case of Jupiter that asteroids cluster here, but wouldn't this be a gathering place for matter to coalesce when the solar system was being formed? Shouldn't we expect small moons/planetoids to be located at these points? (and then of course those moons have their own lagrange points)