That's what lead to things like server side HTML form definition and form handling code.
After the emergence of things like React, Angular, etc those "html templating" facilities get in the way because that stuff is baked into the react app and is focused on the client side, it may get server side rendered with nodejs. A modern fancy web application using React in 2018 doesn't need something like Django forms or Flask-WTF and those types of things conflict and overlap with things like React.
The backend is turning more into a data/API/GraphQL service than "get html" service that was popular when these frameworks emerged.