apparently Adobe is as all the info I've seen is that sites plan to fall back to Flash for browsers that don't directly support H.264.

As for after 2015, dunno but H.264 will most likely be outdated by then - Google to Open-source VP8 for HTML5 Video
http://newteevee.com...-for-html5-video/
On2 went so far as to claim that it could provide “50 percent bandwidth savings compared to leading H.264 implementations.”