Well and fine, but those tools then need to be maintained forever, and they become yet another tool in the stack for developers who come on board to a company w

Well and fine, but those tools then need to be maintained forever, and they become yet another tool in the stack for developers who come on board to a company which has adopted them. It's easier and quicker to learn a new library like React, or even a new DSL like JSX, than a new language.