One of the interesting aspects of the Apple Watch is the large number of customization options coming with it. This takes it close to fashion. In fashion markets there are two important aspects: timeliness and prestige. In general we have fast changing items, really cool, but superseded fast again. These tend to be relatively cheap: lot of throwaway stuff. And then there is timeless luxury. Especially high end watches are jewelry to show off your status, and we justify the high prices to ourselves by assuming that they will not quickly deprecate in value.
The inherent deprecation coming from technological progress limits the appeal as a luxury. I wonder how long the replacement cycle must become before we start to be willing to pay huge premiums for personalization. Cars can last for decades, especially high end ones taken good care of. And we probably still have a couple generations of miniaturization before us before quantum effects make progress too expensive. But Apple has made changing the straps dead simple, the insertion point is flat enough to fit into less thick variants in the future, so you could treat the strap as the jewelry, and the watch as replaceable.
This however does not look like the current Apple thinking, if you survey the current lineup. But if you recall the improvements to the iPhone over the years, it is faster, and has better connectivity and a better camera, but has otherwise remained essentially unchanged. With the display matching the physical limits of our eyes, and processing that can be relayed to the iPhone, the Watch could be much more stable, and settle into a long enough replacement cycle to support luxury.