But once you get a product in market, you start to understand things about the future of that market.

the article clearly says theyre ballparking 100-400k Vision pros and pushing back production of Vision (non-pro). They arent stopping at all, its just a complicated product.

I bet this was Apple's bet on the 'metaverse'. Now that it seems clear it probably isn't going to happen, they look at revising their plans.

Certainly, that's what the reports I've read suggested: Apple seems to be reacting that the demand is unchanged, but they are saying they got hamstrung by an 11th hour supply chain issue.

I can't tell you if that is true or not, but it is a complex product (much more so than competing HMDs, with all those cameras, not to mention unique custom fabrics), so there is enough baseline evidence to suggest that Apple is telling the truth, that this isn't a demand-side adjustment, and that there have been supply chain hiccups that they didn't expect following their launch announcement.

That said I can tell you that Apple's expected demand still sounds startling high based on what I know of the finished product and its cost, so I can agree that a demand-side expectation shift makes sense as a theory, but also Apple is the company that sold millions of first gen products people were skeptical about before and I can imagine Apple doing it again.