In the case of mobile web games, most of the perceived performance gap is due to game engines not optimizing for web experience. If you use a low level Webgl rendering library, or build you own renderer, it becomes apparent that WebGl 2 is capable to deliver a range of products far exceeding what currently exists in that space.
If Safari just allowed users to hide the address/tab bar to play games it would suddenly make web games, of App Store quality, instantly viable.
You can already do this by adding the page to your Home Screen. The real issue is the lack of notifications and access to sensors and device internals.
If Safari just allowed users to hide the address/tab bar to play games it would suddenly make web games, of App Store quality, instantly viable.