Why does FM sound better than AM?

I’m confused how this is even a question.

With AM, anything that causes a variation in the intensity of the signal will introduce noise.

With FM, anything that causes a variation in the timing of the signal will introduce noise.

Unless you’re traveling at relativistic speeds, operating a time dilation device, or colocated with a black hole, you usually aren’t going to see the rate that time flows at vary.

Thus if you can make the amplitude of your signal irrelevant past a certain threshold and embed all the information into the time domain, the only thing introducing interference should be other EM sources that happen to be on the same channel.

That is true for uncorrelated broad-band noise.

Correlated noise (e.g. multipath interference) and narrow-band noise (e.g. another FM transmitter) can both affect FM pretty badly.

Speaking of multipath interference, why is it that we almost never hear the effect of that? Like, aren't these waves almost constantly bouncing off of other things and being reflected? How are we not always hearing echos all the time?