Giving up power makes it easier to write good tools. That's one reason that IDE support for Java is amazing, but IDE support for JavaScript isn't nearly as good

Giving up power makes it easier to write good tools. That's one reason that IDE support for Java is amazing, but IDE support for JavaScript isn't nearly as good - JavaScript allows and encourages way more freeform do-it-however runtime unverified stuff. Java locks everything down with a lot more "must be compile time" and static type system conventions. You can permit the dynamic stuff as an alternative (as Java more or less does.) But if people actually use it, it screws up the tools' ability to introspect into your code. As a result, less-dynamic formats like HTML and CSS get better tooling, as a rule, because the tools have an easier job to do. And highly-dynamic languages like JavaScript and Ruby have terrible tools support, because they make the tools' lives quite difficult because of their language and library design.