Off the shelf, mass-produced, 'one or 2 sizes fit most' seats will never match the comfort of a seat made specifically for you.
Foam densities, dimensions, shapes, etc, all different on one-off 'user specific' seats.
I truly wish I could enjoy an 'off the shelf' seat. Also had an OEM seat 'custom carved' for me by a popular seat modification guy,,, All were better than OEM, yes, but not the best I've ever had.
I can't say for certain that RDL is the only Custom seat manufacturer that works, but it's the only one that has worked for me each and every time.
(Rumor mill has it Russ Meyer and RDL were associated at one time in the past. I believe Russ uses foam only for heavier riders where RDL uses foam and a separate suspension)
I still get a kick out of the aluminum diamond plate seats I see on some Bobbers at the local haunt every now and then! I think I'd rather get smacked in the azz with a cast iron skillet than ride that dayum thing!!!