Not sure how you come to the conclusion on brightness,
I'm not 100% sure on brightness but there are several clues.
There have been several micro-OLED displays show by manufacturers at trade shows and such. They are similar in resolution and size to displays the the Vision Pro. They advertise numbers around 5000 nits.
But because of persistence of vision, the displays in VR headsets only light up for about 1/10 of the frame time, or even less. Otherwise you'd see a lot of blur when you move your head.
So that reduces it to 500 nits.
There are also efficiency losses from the optics that further reduce that.
Even if Apple was able to source displays with twice the brightness and had lenses with twice the efficiency, it wouldn't match up the 1000+nit peak brightness of phones and newer OLED TVs
Another clue: Apple doesn't have the term HDR or XDR on anywhere on
https://www.apple.com/apple-vision-pro/ that I can find. I think if they were significantly better than other VR/AR systems, they'd highlight it as a feature.
But a low peak brightness isn't all that bad. Movie theaters are supposed to project at a maximum of 48 nits.
Dolby Cinema has a peak brightness of 106 nits
IMAX has a 75 nit maximum.
OLED TVs have infinite contrast ratio, so the Vision Pro can't exceed that. All VR systems have had some level of glare from lenses. We'll have to see how good Apple's lenses are, but there will be compromise somewhere.
The AVP displays ate 3648*3144 resolution, or very close to that. Multiply that by 2, and you get the 23 million pixel value that Apple gave. Apple has also shown representations of the display panels, so the aspect ratio can be determined from that.
A 4K TV is 3840 pixels wide. The AVP may look close to that, but you can't actually use the full width. The FOV of the AVP is likely 100°+, and IMAX theater screens are about 70° for the average seat in the theater.
OLED tv and display in the AVP are the same. Both use filters.
How can the AVP be less bright, contrast and resolution?
There aren't lenses between my eyes and my OLED TV (except my contact lenses). The microOLED displays are better than my TV in some ways, but not by the time the picture reaches the viewer's eyes.