But what is the future? A little card displayed in front of your eye? A little card displayed on a watch? A slightly larger or smaller screen?

None of these. Consider the only way to beat entrenched competitors is to leapfrog their technology. You can’t beat Apple by building a better iPhone and you can’t beat Google by building a better search. You must obsolete the old technology with something disruptive and move customers over to the new thing while the old thing lives on. The car didn’t displace horses. TV didn’t displace radio. The Internet didn’t displace TV. JavaScript didn’t displace PHP.