Actually isn´t html5 cross-platform? No gtk, qt, proprietary bs, works (hopefully) on every platform?
Maybe some day we can choose whether we want a M$ kernel or linux, and all the apps will work. Those who want a slower device with more crashes and that costs and that cripples your freedom, can choose the monopoly/mafia os and the rest can choose Linux.

Maybe the desktop distros should start thinking about html5? The sofware companies could finally make really crossplatform games and other apps. Don't worry, it will never happen...