What does "more VR than AR" even mean? Either the user is seeing virtual objects overlaid on the real world or not. It has nothing to do with the opacity of the lenses.
I've found the Meta 2 AR headset to be quite dark (and it's still not quite as dark as what was shown in the pictures in the article) and it becomes very difficult to look at the graphics and understand them as part of the real scene behind them. With the real surroundings so darkened out, it creates a completely different contextual space. You definitely get to a point that you forget to pay attention to the real space and only pay attention to the visualization on its own.
So that's what "more VR than AR" means. Continuity of context between real and virtual is the defining attribute of AR. Without it, you just don't have AR.
If you can't see much of the real world (15% light penetration by this account), how useful is that overlay? If it was 1% light penetration it would look almost completely black, to the point you may not detect any real world at all. At 99% light penetration, you probably can't even tell there's any shading at all. Somewhere in the middle different people will draw the line as to what's usable as AR and what isn't (and even then, it may depend on the action being attempted).
Because they might have no choice. The million (billion?) dollar question is: are they full of bull? That’s what this is all about.
He’s saying: they want to go higher than 15%, but they can’t. Not ‘they choose not to.’ They would have if they could. And they can’t go 0% and full VR because that would be admitting defeat, and the end of the gravy train.
I'm pretty sure this is deliberate. Remember when they said they could make projections opaque? And they said some waffle like even though it is impossible in theory, in practice you can do it.
It looks like their solution is to make the glasses dark, so that in comparison the display is very bright. If it is bright enough compared to the background you won't see what is behind it. Making the glasses dark is probably ok because your eyes will adjust (your eyes have an insane dynamic range).
Also, realistically even with AR you spend most of your time looking at the augmented part rather than reality (based on my experience with the hololens anyway).