I’m pretty sure the reverb does fewer cycles than the revelation fork on the front so how come fork bushes last a lot longer? Reverb is sloppy in less than 2 years. Plus I think the seal on the IFP is no longer working 100% as I’m getting 5mm of sag on the post.

No one knows then?

This is my best guess:

Forks have bigger diameter stanchions and there are two – I’m guessing the fork leg can accommodate a much bigger bushing – could this be distributing the pressure/load over a greater area?
There’s probably a lot more lubrication in a fork leg.
Does a Reverb have keyways like a Joplin? These stop the shaft rotating but wear which causes the movement.