AKA laziness. yes, lets please bloat of the scope of browsers until they are no longer recognizable, so that you dont have to install some software.

You oversaw the untrusted part, this is the only reason I prefer web over native really. If there was a way to run native apps with that level of isolation, I would prefer native.

Snap, Flatpack, iOS sandbox, Android sandbox, UWP/Windows sandbox,...

Unfortunately, none of those are cross-platform... Closest we get to something similar to the web is either the JVM or APE (Actually Portable Executable) but then those are generally not as isolated as the alternatives you mentioned, sadly.

Or CLR, or now the fashionable WebAssembly.

Plus, plenty of languages have cross-platform runtimes and libraries, so not a big issue, not everything needs to be JavaScript.

Instead, you're executing untrusted browser code, which is hardly better.

I'm interested if this is true. It seems like the js sandbox is pretty well implemented now in most cases. Webgl had some problems at first leaking host data, but the willingness to sacrifice performance for security seems pretty ingrained in these consortiums?

I don't understand how you can possibly say this with a straight face.