Well one, it *can* be solved, and in fact for experiences that do not move the user at all, almost no one gets sick.
Those that place the user in a cockpit, and move the player around relative to the outside, but not the cockpit, sickness correlates closely with rate of motion sickness in cars and boats and such.
Even those that move around like crazy, sure more people get sick, but in my personal experience, I'm not even sure it's a majority.
The short of it is, if you are interested *demo* it for yourself. Don't just assume you will or will not get sick, because it's your own vestibular system and there's a great deal of variety.
Microsoft is also not really going straight for AR, they did do Hololense, but Windows Holographic is intended to support both VR and AR, and the affordable hardware is going to be VR first. AR still has a big problem of some technology that allows seeing the outside world and seeing the overlay. Problems with how ghosty the content is, and/or more critically ability to project over a wide field of view. In VR, they distort the hell out of the screen to get wide field of view, but in AR that can't be done because it will distort the real world. Also AR can't provide the same total immersion as VR if that's the goal (well it can, but by covering up the whole world, in which case it's really VR).