This is not true at all, modern component based projects like https://element.eleme.io/ work perfectly find in mobile and you only load the CSS/HTML/JS per component so it doesnt need to load tons of JS just to render simple form or UI components from Vue or React.
I literally watched the select dropdown jitter all over the place scrolling on mobile. It's bad. The native controls don't require a library and are fine. And all of the event handling and HTML5 form validation works as expected.
