Also enough good programmers. You could have the most perfect programming language in the world, but if not enough people know it, it's not going to get deploy

Also enough good programmers. You could have the most perfect programming language in the world, but if not enough people know it, it's not going to get deployed and get into the world. JS is not around because it's some paragon of programming language, it is just smashing everything else frontend wise in terms of developer numbers.