[toasterlovin]

> If you don't want to use a web browser with a third party rendering engine, you could just not install it.

It's not that I don't want to use a 3rd party web browser. It's that I don't want a 3rd party web browser to ever become popular enough to give that browser's vendor the ability to influence Apple's ability to make technical decisions about their platform. Being beholden to 3rd party software vendors was basically the story of OS X for years. I don't think it was good for Apple.

> As other comments mention, all a mandatory browser leads to is "you must use IE6 to visit this site"

On the contrary, as long as Apple is Safari only and Android is mostly Chrome, there is no way that this can happen.