"As much as many people want alternatives to JavaScript, there are also people who consider themselves JavaScript experts (or the various related languages like TypeScript). They’ve invested a ton of time and effort into getting to where they are."

I do not see a problem here. The idea is not to replace js (not realistic anyway), but to have a full working alternative to not have to use js anymore, so in the end you can really choose how to build for the web.

I also invested heavily into js ... but I am really looking forward to the day, I can use something sane again.