Extremely true. Rolex and PAMs have much higher resale and trade in values. I found this out firsthand when I was inquiring about possible trade ins. IWC and even JLC as a whole don't hold up their value nearly as well ( as I would've liked)
It made me really appreciate Rolex a little more to be honest.
A buddy of mine discovered the same thing with both a IWC and a stunning 8 day Master Reserve limited edition. The store owner came out and said, Sorry, I'm not even interested in seeing IWCs or JLCs...our customers really only want Patek, AL&S, AP, Rolex, and Cartier. And my friend's limited edition JLC is a real beauty!
Not sure if they would consider a PAM, but as you already know PAMs have traditionally had very strong resale value.