a) HTML/JS cannot be used to develop cross platform applications and you must target a very specific rendering engine implementation in order to achieve some kind of usefulness,
b) Google's developers are muppets and can not code their way out of a paper bag,
c) Google is lying.
Easy, it's C. You see, please let me tell you a little history lesson. It used to be that, in my life time, Microsoft was the 800 lb. gorilla that no one wanted to mess with. Everyone wanted to be its friend. Why, people even wanted to pay money to get its certifications. Mothers said to their kids, if you wont eat your meat, Microsoft will come and take your toys. Life was good. But suddenly, the gorilla discovered that the times were a changing. There was this new kid that was talented. Not only that this kid made many awesome toys, it open a lemonade stand and everyone came to drink. I mean everyone (I just saw Coca-Cola the other day).
This gorilla was kinda old and knew it's gonna bite the dust one day, so it had a baby, it named WP7, later to be renamed WP8. The gorilla loved the little ugly baby (just teasing you), and said to all the kids you better watch my baby, or else... Then the cool kid said no way that gorilla's baby going to drink at my lemonade stand. No fscking way. Suddenly the poor gorilla found itself in a terrible (so it thought) spot....
To be continued