Neptune is profoundly anomalous when it comes to moons among the gas giants. Jupiter has its four massive moons, Saturn has a several large spherical bodies and Uranus, a world similar in size to Neptune has five or so major moons.
Yet Neptune, the ice giant which sports one of the largest hill sphere radii in the solar system only has one major moon, of which is likely to be ripped to shreds in the future.
I find it peculiar because Uranus has five major moons yet Neptune only has one major moon. What explains this disparity? Did some disruption happen to earlier moons Neptune may have had? What's known about this?