I think a key difference is that Apple had a very clear target demographic for the iPad in mind (lightweight laptop / heavy phone users), and then were prepared to see how it evolved on top of that premise.
With the Vision Pro, they haven't been able to articulate their target userbase at all, and are pretty much relying on the early adopters to help define it for them.
Which isn't to say it can't find its place and be successful. But I don't think it's anything like Apple's other product releases at all...