Which means "unsexy" things like accessibility get left by the wayside. And your users suffer.
Writing a UI kit is a huge task. It's one of those things (like so much else in our industry) where you can fairly quickly climb "stupid mountain" by getting a pile of shiny widgets on the screen; but then you look out over the valley below and realize that, holy, crap there's a whole other mountain range of things that a UI kit has to do.
It's also a tough story for Rust, in particular, because copying what other people have done with other toolkits won't really cut it. Rust's ownership semantics and general opinions don't necessarily accord well with the highly object oriented and event-loop / object-tree structure of most existing GUI toolkits.
Aside: I still don't understand why things like Electron based apps are so bloated. They seem to static link whole chunks of their own (forked) Chromium. But both Windows and Mac OS ship native webview components as part of their system which can be used instead. I've done this myself (used Edge's Chromium webview component in a VST synthesizer, and equiv webkit stuff on Mac) and binary sizes were entirely reasonable. Linux was a slightly more complicated story.
