The answer is bit paradoxical: It is because JavaScript itself can change only very slowly. What you see changing is everything around JS but JS itself, while p

The answer is bit paradoxical: It is because JavaScript itself can change only very slowly. What you see changing is everything around JS but JS itself, while powering the whole web, is still to an extent the same scripting language that Brendan Eich prototyped in 10 days back in 1995. Why is that? Simply because the JS runtime environment - the browser - is not controlled by a single entity that could plan and enforce radical change. Instead all the big players have to progress together, which is usually not in the interest of all of them at the same time (It used to be Microsof who was not interested in progressing the web standards, now it seems to be Apple. Not because they are bad people but because it makes sense in their situation.) Plus you have to maintain backward compatibility with older browsers, one can still not simply use ES6 in production website because it would not work in significant portion of the (older) browsers. That is why everything around JS changes so fast in an attempt to find the best workaround, polyfil, transpiler, module etc.