If HTML5 is the future then Google needs to accept it as a native programming language for Android.
Android is an operating system and as such needs to be able to control hardware functions. This and the reason that every phone manufacturer uses different hardware is why Google finally went with Android which is Java/Linux based and we know where Java excels, compatibility, it runs everywhere.
A game does not need to control hardware, rarely it would, a web app probably requires more hardware control than a game will ever need. The only think a game requires is to be able to access the video card and sound card and browsers can use hardware rendering already sometime now.
There are several reasons why you would not want an operating systems in HTML5 either, mainly security and its not ready yet for that kind of low level hardware operations.
Google does believe HTML5 is ready for gaming as well as they are the ones that launched the website
And it has a full section just on games:
The only limiting factors where always browsers, why where we not able to do even the basic things we can today on the web some years back? RAM was there, CPU was there, but browsers where still mainly only for web page content, not multimedia.
Because browsers where slow adopting new changes. Google Chrome changed that and everyone is developing their browsers in a fast peace, even Microsoft supports HTML5 because they are forced too, and Windows 8 is heavily promoting HTML5 for their metro apps as well.
As browsers keep evolving and integrate better with hardware in the future, there are more and more things your browser is going to be able to render.
Would someone had expected something like this in their browsers years back, when they had to buy a full computer to do this and just play a basic game?
Something as a full computer from decades back work in a browser.
In 10 years from now, you are going to be able to render in your browser similar games you can run in a PS3 console now.