Hard to say, but I would guess that by the end of this decade more people will be wearing XR glasses than those still looking at smartphones. My guess too is the price will never be less than an iPhone today but the value will be higher as it will do more. A lot more.
These are the limitations of the tech today, but a wave of innovation is inbound. 7 years from now XR glasses are going to much more slick and solved many of the issues you have raised. If not 2030, some point before 2040 unless we go extinct first.