I think it would be adopted exactly as widely as JavaScript is. People choose JavaScript because it is supported by the browser, not because they think it has

I think it would be adopted exactly as widely as JavaScript is. People choose JavaScript because it is supported by the browser, not because they think it has a beautiful syntax. If some other language has been supported instead (whether VBScript or Scheme or whatever), people would use that. Semantic markup languages were niche until the web happened. Objective-C was a weird niche language until the iPhone app boom. People learn the languages they need to learn.