JVM has many competing implementations[1]. Also it is not used by clueless end users, but by tech workers. They will protest is JVM gets "phone home" "features" and other bloatware privacy-killing crap.

End users of browsers do not have this insight into their tools.

Yes, Oracle's JVM is dominant (but not on Android, which is a huge installed base). So is Chrome in browser land. Still good that Java has many, and FF exists.

[1]: https://en.wikipedia.org/wiki/List_of_Java_virtual_machines

I hear this argument, and it makes sense...

But a lot of us still pucker up if you mention the word "IE6" and we never want to risk going down that path again. :)

There's a balance between diversity and monopoly that can be struck.

Same with the Linux kernel and it's got a larger codebase than Chromium.