This seems to me a bit like saying we could never have a flat tablet computer because its impossible to have a perfectly flat crt that's thin enough what with the magnetic yoke, the electron beam, shadow mask etc.
"Breakthrough" is used much too often these days. Breakthroughs are breakthroughs because you don't see them coming. It will be laugh-out-loud unexpected when it comes, seem obvious in hindsight, and be one of the few things ever invented that might deserve a patent monopoly to be granted for a small handful of years.
I agree, and I think the author would too - the key phrase in the headline being "Anytime Soon". I think he expects a breakthrough to happen - but remember that there's generally quite a bit of time between the initial breakthrough and its feasability for large-scale consumer applications. The first LCD display was created in 1972, and the first patent of the underlying technology was issued in 1936 to the Marconi Wireless Telegraph company. I don't remember seeing them in Wal-Marts until the late 90's at least.
The time stays the same since as ambition grows, the difficulty in prototyping and producing a product increases. Any gains made in rapid prototyping are offset by higher goals.
That point is already adressed in the article, he says:
"Hard AR is tremendously compelling, and will someday be the end state and apex of AR.
But it’s not going to happen any time soon."
Then later:
"Of course, there could be a technological breakthrough that solves this problem [...] In fact, I actually expect that to happen at some point[...] But so far nothing of the sort has surfaced in the AR industry or literature[...]"
"Breakthrough" is used much too often these days. Breakthroughs are breakthroughs because you don't see them coming. It will be laugh-out-loud unexpected when it comes, seem obvious in hindsight, and be one of the few things ever invented that might deserve a patent monopoly to be granted for a small handful of years.