Karl Guttag has a history of getting a lot of excruciatingly difficult details right, and missing the literal big picture right in front of him. I think he makes great technical contributions to the field (at least from my perspective as a layman), but every one of his analyses that I have read ends with something to the effect of "and this is why it is physically impossible for AR/VR to ever work", which is far beyond skepticism. It makes it hard to take the rest of his analysis seriously because it shows an irrational bias against the technology.