You assumed that models would stay that price forever???
"how brutally Apple treats developers with their in-app-purchase nonsense"
How is 15% brutal to have access to a market base of hundreds of millions of customers who can click to purchase without entering a credit card.
"Apple itself sure isn't doing anything to put any wood behind the arrow"
Of all the dumb things you said, this may possibly be the dumbest - though to be sure the other two items are incredibly stupid.
Apple has put a TON of effort into the Vision Pro. They have continued to produce high quality immersive content. They have obviously continued to work on new versions. They have recently put on an entire developer day program on producing immersive content (programmatic and video related). They have greatly improved the Mac mirroring features and added other good UI updates on a pretty continuous basis since launch.
Apple is doing all they can to move the platform forward, it just takes time to reduce costs. It's a platform well worth looking into supporting since Apple is obviously fully committed to it moving forward.