It's not possible. As soon as WebAssembly gets as big as the web, someone will implement a browser-embedded browser in WebAssembly that runs in the browser and we will be back to square 1 in this kafkaesque nightmare we call Web.
From: https://www.destroyallsoftware.com/talks/the-birth-and-death...
When I got into computers it would have been ridiculous to imagine carrying around a computer running a different OS in a virtual machine, within which we were running a virtual network of small virtual machines existed to run programs written in a scripting language that itself runs in a VM!
Sounds crazy, right? And yet it isn't rare to find a developer on a Mac laptop running Linux in VirtualBox, inside of which they run Docker containers to run applications built on node.js. This is not done as a joke, it is done because it is a useful development environment for an application that is supposed to eventually be deployed to a cloud.
Portable software has been a motivating dream of our industry since forever. It was a selling point of COBOL, Pascal, HTML, Java, Flash, JQuery, and so on and so forth. The idea of deploying a known client target to get rid of browser differences is inevitable. It is just a question of who will be the first to do one that is good and fast enough to get mindshare.