Says who? Is Apple going to make the entire Vision SDK web compatible?

Safari was shown in the demos.

The question isn't whether you can view the existing web content on the Vision Pro, the question is whether all of the Vision Pro SDK, sensors, and 3D functionality is exposed to the browser to enable VR-enabled webapps for the genres which Apple would disallow on their app store.

Neither a web browser, nor the iPhone are remotely comparable to a general purpose computer in terms of free use

I've never understood this criticism of iOS. It is a fully fledged general purpose operating system with bare metal access and ability to run anything that can be compiled. Sure you can't distribute apps that do whatever you want on the app store. But there is absolutely nothing about iOS that makes it any less of a general purpose computing platform than Windows or Linux.

Many of us learned development by using a computer to program apps that then ran on that same computer.

As far as I’m aware you can’t do that with iOS devices (potentially including the AR ones).

>As far as I’m aware you can’t do that with iOS devices (potentially including the AR ones).

Sure you can. You can fire up Xcode right now and build a self signed app to your phone with whatever the heck you want in it. Distributing that on the App Store is another story, but there's nothing stopping you from executing whatever arbitrary code you'd like on your own phone.

This misses the "same computer" stipulation, no?

On iOS you don't have root. This prevents you doing many things with it, which is why jailbreaking exists. The fact that you can write an app and deploy it directly to a restricted number of devices for testing (if you're on the Apple Developer Program and own a Mac) doesn't change that.

Try altering the iOS home screen behaviour, directly accessing the filesystem, writing your own device driver or tweaking the kernel. You certainly don't have "bare metal access" except by voiding your warranty and risking bricking your device by jailbreaking it, if there even is a jailbreak exploit that currently works on your device.