Scarcity for many brands is due to COVID, just like everything else. There can also be market area issues (JDM/etc. only watches are still a thing).
What I am not sure is how much the reaction to the grey market has contributed (in amplitude or percentage of the problem)
@Priller , a decade or so ago ADs were dumping excess inventory into the grey market where it was sold retail at a deep discount. The brands were spending a lot of time trying to identify these dealers to shut off the flow (and shut off those dealers). Not long before COVID hit Costco had new grey market ~$3400 Speedmasters, Monacos, etc., and that is CDN BTW!
Recently the grey market has changed and is instead selling hard to get models at a significant premium. Specially in the context of COVID shortages.
Of course dealers want to make money and sell watches, but they have the same COVID delivery issues other industries have. They want to make sure that regular/repeat customers get product vs guy off the street (they have one Submarniner...do they sell it to guy that spends lots of money there or some random?) and they are paranoid about grey market guys scooping inventory and getting in trouble with the mothership.
Of course some brands could just be implementing the Ferrari model...
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PS, what does make me sad is that the doors are locked these days I know have to call in and even sometimes book an appointment to go into the store. I miss just going in and browsing to see what is new. AFAIK this was at least partially due to COVID control but mostly now due to smash and grab.