mostly theora lost it's momentum because during the web video "debate" there were many articles shitting on theora for not having hardware support and being slightly to fairly worse in various cases.
and now they need a new attempt to get people back on the open codec wagon.
And they have a point: the _screen_, radio, etc. (http://www.ietf.org/mail-archive/web/rtcweb/current/msg03785...) of most mobile devices is already using something like 90+% of the power, so even in the impossible case that hardware accelerators make decode itself use no power they can't make that much of a battery life difference, so long as the device was fast enough to decode in the first place. And this trend will only continue as devices becomes faster and process shrinks lower the computing per joule.
But it's amusing to see some of the same people arguing that hardware accelerators were _must have_ are now arguing the opposite now that its their latest format which is suffering for the lack of them.
Remember that it wasn't just hardware decoders in end-user devices. H.264 already had a lot of buy-in from video producers. With support at both ends of the chain, trying to replace it just for the sake of patent issues (which most people didn't care about) was a fool's errand.
and now they need a new attempt to get people back on the open codec wagon.