Do you mean it is amazing how poor is an experience and how many features, widgets and controls they lack when compared with something like FPC/Lazarus and Qt?
Rust is a nice thing, but its UI ecosystem simply cannot even compare.
What's interesting is the speed at which Rust UI toolkits develop and maybe even mature.
It doesn't matter how many of Rust UI toolkits there are. Consider that there are a lot of Rust game engines, and pretty much zero games written in it, because even C++ gives you better trade-offs in that particular space.
I've tried using Qt (non QML, using rust-qt) last week... initially things were looking fine (despite unsafe everywhere)... but I found quickly that I need unsupported things (deriving from C++ classes), and the project isn't really maintained anymore, so I'll need to so some low level work myself if I want to proceed.