Fuck, I just wrote a whole reply, and I hit the wrong button and it got deleted.
Ok, if you look at what the auction houses and pre-owned dealers are selling watches for compared to retail (to say nothing of arguing price with the dealer and getting a discount), you will see that BP's (and VC's for example) fare less well when it comes to resale value than PP' or AP's. I am comparing from the simplest ultra thin watch to the most expensive super complication.
Hate it when that happens...
Interesting observation; thanks. I should have actually not mentioned AP; just don't follow them that closely.