One thing I'd note is I think people are over-estimating how quickly the price will come down, especially if the initial demand is strong. I don't think there will be a version of Vision Pro (or Vision Air?) that is $2k or less for at least another few years. Maybe the 2nd gen of Vision Pro will come down in price by a few hundred dollars, but again maybe not if the demand is strong even at $3,500.
The product line will last as long as it sells. Even Apple TV which had shaky sales to start has persevered. Apple doesn't necessarily have a long history of backing out of core products unless they've been eclipsed by something superior (see iPod -> iPhone).
My uninformed, armchair bet is that Vision Pro will be the Pro device of the Apple Vision devices, and the 2nd model will be a cost-down non-Pro variant, to still be sold alongside Vision Pro as the top-tier device.