I'm sorry but tetris isn't exactly state of the art in game design these days. We already have tons of games that javascript/html simply cannot even come close

I'm sorry but tetris isn't exactly state of the art in game design these days. We already have tons of games that javascript/html simply cannot even come close to handling. Naturally people are starting to think about how we can get there, while maintaining all the benefits of a dynamic runtime. So the point is that what javascript is today is not good enough, thus the exploration into how to make it faster.