[koolba]

In what world can you modify the OS to add something like this but you cannot modify the OS to install a better browser? (Or a better OS!)

[hollerith]

ChromeOS puts Chrome in a nice safe sandbox (in addition to the sandboxing of Chrome tabs that happens on all OSes) that used selinux and other technologies. This requires modifications to Chrome. Replicating that for another browser might be harder than modifying ChromeOS to add something like this.