On x86, the only real "sandbox" you have is what your MMU gives you. For as long as executable has access to browser's address space, it can do anything a browser can, including reading your webcam, mic, sensors, GPS, etc
Thank you. We have a winner here! And the people trying to escape them will have the full capability of native code running on your CPU.
In the mean time, permissions will be granted for ever increasing parts of the system. Users will not be prompted to "allow" for every site they visit because that will be tedious so browsers will start the enable permissions by default. But either way, we now have the browser acting as the keeper of permissions that our OSes are not able to enforce at the granularity we need for such things.
We've been continually migrating the browser to the role of an OS. It's just insane.