Rolex says that its watches “are known to retain and/or increase in value [after purchase],” making the purchase of a new or “a pre-owned/vintage Rolex watch highly regarded in the watch industry as a smart and reliable investment”. I wouldn't say reliable investment, it depends. But sure Rolex is made of expensive materials, and I think that's why when you sell even an old one, it still be considered very valuable.
Rolexes are largely brass and steel. The ones that are commanding the highest premium over list right now are the steel sports watches; nobody is paying through the nose for the gold models. And from a horological perspective, Rolex is considered a "designer" product, in that it's not a low-end ("fashion") watch like a Tissot or a Shinola but it's also not a high-end ("luxury") watch like a Patek or an Audemars. I changed bands on a Gauthier last summer that costs fifteen times as much as any GMT Master you care to buy and that Richard MIlle that Odell Beckham wore on the field is mostly carbon fiber. Rolexes are valuable (within their channel) because they have brand recognition. They're 70% of the mechanical watch market. And they have brand recognition because they make a reliable, identifiable product. What they're doing here is definitely in their best interests from that perspective, but it's likely to bite them in the ass in the long term. They used to be a much more innovative company but they've been stuck making basically one watch that isn't expensive enough to rest on their laurels.