It is because JS does not change much that there are all this libraries around that changes a lot to try to give an underfed horse more power. In comparison, j

It is because JS does not change much that there are all this libraries around that changes a lot to try to give an underfed horse more power. In comparison, java, PHP have undergone some more than welcome mutations in terms of syntax clarity. Evolution in JS is made by adding features in frameworks, not in the core definition of the language. You could see JS as the assembly language of the browser and all the frameworks as some C/fortran/C# that translates into JS. The problem is the web would look definitively balkanized/ghettoed between old and new computers if you made a non backward compatible change of JS ... JS is the most ducked taped language of the landscape of computers. And it is leaking memory, performance, abstraction from everywhere.