so does the concept of the 'browser is the OS' , improve security? Is it analogous to a hypervisor running on a server somewhere, then when you log into the ser

so does the concept of the 'browser is the OS' , improve security? Is it analogous to a hypervisor running on a server somewhere, then when you log into the server, it spins up a vm os just for you. Now any hacking done on that os is isolated and disappears when that instance is closed. in the same way, when the browser is the os, none of the files,apps or stuff on your machine is available to it?