"So they stick to adding lipstick to the pig. But JavaScript isn't like other languages: its fundamental errors are so glaring, and impact so negatively on the language, that the benefit of jumping to a "JavaScript 2.0" massively outweighs its incompatibility disadvantages."
"Jumping to a JavaScript 2.0" is the hard part. Any successor to JavaScript has to have a compatibility story with all the JavaScript code out there, as well as the DOM APIs and so forth. Either you ship two VMs, in which case each page has two incompatible worlds (yet both can access the DOM -- think about the massive complexity this entails), or you have to think about language versioning, which requires at the very least a functioning static module system.
The biggest challenge with multiple VMs is doing GC over both: cross-VM GC is a current research topic, and nothing has shown to be doable without a noticeable perf impact.
"Jumping to a JavaScript 2.0" is the hard part. Any successor to JavaScript has to have a compatibility story with all the JavaScript code out there, as well as the DOM APIs and so forth. Either you ship two VMs, in which case each page has two incompatible worlds (yet both can access the DOM -- think about the massive complexity this entails), or you have to think about language versioning, which requires at the very least a functioning static module system.