You speak of the "installation barrier" as if it's something insurmountable. But why should it be? A native app zero-install mechanism seems more plausible to me than wide adoption of a hypothetical geolocating proximity web.
The reason is that native apps can move so much more quickly than web apps. I'll bet Apple could get widespread adoption of a zero-install feature on iOS in six months, simply by mandating it for the app store and featuring early adopters. But HTML5 YouTube has been in beta for over two years, and the <video> tag was introduced over half a decade ago. The web moves at a snail's pace by comparison.
I did try to watch the video, but scrubbing didn't work, which sort of illustrates my point.
