Zero-install is not difficult. In fact, it was around decades ago. Then people destroyed that with complex operating systems requiring loads of configuration. Even with the stupidity of modern operating systems we could recover zero-install with simple virtual machines (or any number of other mechanisms).

Web links are cool. Just about the only redeeming feature of the web. They have absolutely no connection to JavaScript, HTML5 or any of the other hideous complexity you see in the browser.

Browsers are not "zero friction" upgrading. Behaviour changes from version to version. Using Firefox on Linux I have experienced continued breakages. Again, if you had a simple virtual machine it would be simple to port anywhere, and you wouldn't need constant bug fixes.

Your last point has nothing to do with technology. It is simply the result of vendors successfully selling the technology to people. By doing so they've locked other better approaches out of the market due to network effects.

The remainder of your post is the good old "it'll be good enough" attitude. Except it won't ever be as good as it was because people are reliant on benchmarks that make "freight train" style systems look "fast" for through-put code.