Even if the web is the last place to adopt it I would still like to see an effort sooner than later simply to fill the gap in functionality left by jpeg/png/gif that jpeg xr nicely fills.
From what I understand, there's relatively low interest to photographers in jpeg-xr at the moment. Camera memory has become so cheap in recent years it's now practical to shoot everything in RAW. Photoshop CS6 does not support JPEG XR. Though I do think Jpeg XR would be useful in this area, I don't think it's something camera manufacturers are rushing to adopt.