AR glasses won't be a thing until they stop trying to put a tiny TV screen in front of your face. It needs to fill your visual field.
They also won't be a mass adopted thing until they don't make you look like an 80s cartoon character.
The question remains whether VR will still have it's time before AR becomes reasonable.
Until that is answered, VC money will continue to be sacrificed in a giant fire on the alter of getting there first.
The problem at the moment is we are technologically well behind where we need to be to make practical AR in terms of screen resolutions.
I think the screen resolution isn't that big of a deal for many applications (mostly games and stuff like it), and it's not like it's impossible right now, just expensive.
The bigger hurdle from where I'm sitting is getting framerates and latency in a good position. Everyone I've seen use a current gen VR headset gets horribly motion sick in a lot of cases. That NEEDS to be fixed, and I think that comes down to crazy high refresh rates, and super low latency, both of which really crank up the processing power needed.
But regardless, I don't think resolution is going to be what makes or breaks VR/AR. We worked with computers just fine when they were ~500 "pixels" tall, and it's not like screen resolution technology has hit a wall that it can't get past yet, things are still improving.