How many phones out there are capable of integrating this into their firmware, download the software to begin with, yet don't have touchscreens, all while still being in service. I just don't see any situation where a phone doesn't have a touch screen, yet would be enhanced by one. Aside from maybe older keyboard based phones, like earlier Blackberries... but that still leaves the question of getting it in and having it be worthwhile.
This says nothing, of course, about the user themselves. Even if you could get it implemented, most people who don't have a touchscreen don't really want one, or are planning on getting a new phone soon enough.
Of course, there still will be plenty of people who this won't help at all who will get this anyways. It will be like 3D movies. Not everything was meant to be in 3D, but people will still go to the 3D showing by the truckload.