JavaScript lives on. It's not just inertia. IE for example supported multiple languages at the same time. As a lingua franca, JS is simply better than the alternatives.
Python is subjectively cleaner than JS, but it isn't sufficiently better to warrant replacing JS, especially after JS started becoming more Pythonic. Lua is arguably a step backwards. Go adds a necessary compile step. Folks already gave Java a shot. C/C++ was a hard-learned lesson after ActiveX regarding web security. Perl ain't gonna be it obviously. Rust has a much too steep learning curve for the vast majority of web developers to tolerate. Ruby is slower and also not sufficiently better.
I know folks don't like to hear it, but JavaScript is nowhere near as bad as folks like to go on about it. In fact it's so flexible, an entire ecosystem rose up around it on the server side more than a decade after its client-side debut. If JS were really that bad, no one would adopt it for other areas if they didn't have to. It is familiar and gets the job done. We only highlight its shortcomings because we've had almost 30 years to pick it apart and dissect it.
Google could team up with Apple and make Swift a supported language. Within 2 years, it would be on >90%+ of all devices. Maybe 95%. And it wouldn't matter. Sure, a bunch of folks would use it, especially if they were Apple devs. But the vast majority would ask, "What would this new language give me that JS can't do? Is it actually worth rewriting apps and retraining my staff?" Honestly, the answer is 'no'.
Because JS really isn't bad. It has warts (though many/most of them due to the DOM rather than the language). It has legacy. But after 30 years, it's still doing surprisingly well at both speed, flexibility, and the ability to evolve.
VBScript, I'm almost willing to cede. That said, I don't remember it ever being a thing that websites tried to use. Even back in the days of them ripping off Sun with JScript. I'm also curious when they had 90% of the browsers with it? Would love to see a solid timeline on that.
Note, too, that I never pushed that JavaScript is bad on this. Indeed, I agree with you that it is nowhere near as bad as is often stated. What it lacks, is discipline. Which is why it seems to have near every paradigm accounted for nowadays.
That said, /if/ Google teamed up with Apple and got that pushed on all devices for native, I suspect you would see it leak into the browsers in that 2 years and that we would indeed start seeing more Swift developers at large. And a ton of "reasons you should migrate to Swift" for your websites.
Internet Explorer had 90% marketshare in the years around 2004. Netscape was dead. Mozilla/Phoenix/Firefox was a hopeful, not a contender. VBScript was everywhere IE was, and folks still preferred JS, even if their sites proudly proclaimed "Best viewed with Internet Explorer". In the late 1990s/early 2000s, MSDN was full of examples pushing VBScript. It became second nature to myself and coworkers to just reason out what the equivalent JS looked like on the fly. Microsoft absolutely tried its best to replace JS, but devs wouldn't have it, and the number of JS-powered sites was just too large for Microsoft to simply drop compatibility.
It was around that time that Microsoft stopped making updates of any kind to Internet Explorer for years. Folks today really don't comprehend the debt we hold to Mozilla for breaking out of the notion that the web was feature complete.
