Google Glass first of all has not come out--yet. only developers or those who bought the more-expensive models to test out have them.
Google Glass also has no future plans on replacing smartphones. as i have said, the trend is to the "bigger is better" mentality, both in hardware and apparently UI design. try using the new Play on a Nexus 10. the size of the elements makes that 10-inch screen pointless. it looks more like viewing DesqView on a CGA monitor. a total shame that my Nexus 10 has such a high-resolution, extremely high PPI density to be lost in the transition to flat-UI design instead of 3-D. tech was once seen as getting smaller and smaller to where it became integrated into watches, or even people. cell phones showed a trend towards that in the 1990s by getting smaller and smaller, but now everyone is sporting huge bricks again, and the progress isn't towards integrated tech but just modernizing older tech from some decade back
Believe me, i was there. i was there in the age of CGA and DOS, UNIX and CP/M. i remember early GUIs very well. these days they call it 'modern UI' but all i see is a kinda modern-ish take on those early GUIs.
We also have no idea how the public will take Glass. it could just end up faltering like the Nexus Q, Google TV, and Google Wave, and people might just prefer tapping away at their modern take on a Palm Pilot with their Stylus--i mean S-pen. it would not be the first time the excuse 'the world wasn't ready for it' came up. look how long speech recognition has been held back!
Samsung Galaxy Note 3 (rooted, HyperDrive ROM)
Samsung Galaxy Tab 3 7.0 (non-rooted, stock)
Samsung Galaxy Tab 2 10.1 (obsolete, slow, rooted)
Samsung Galaxy Note 10.1 2014 Edition