They either have to bring SIMB to every language or to none at all? They want to improve web application performance. JavaScript is the only language that work

They either have to bring SIMB to every language or to none at all? They want to improve web application performance. JavaScript is the only language that works on the web. So they are bringing it to JavaScript. That doesn't mean they won't bring it to other languages in the future. It doesn't make sense to improve HTML5 game performance by bringing SIMD to Lua or Python.