I think you are overestimating the ease of building UI controls. WPF for Windows represents the most advanced system that Microsoft developed, it's very complic

I think you are overestimating the ease of building UI controls. WPF for Windows represents the most advanced system that Microsoft developed, it's very complicated, and there's no real equivalent API for web. The concept of WPF's Visual allows deep customization of a control and lets you build your own primitives. You could build your own Clippy.