I'm sure it shrinks the footprint a lot to just do "widgets" rather than being an effective VM, but even that is plenty huge. I'm not aware of any "non-mainstream language" having even that much of a toolkit. Plenty of partial starts, even starts that with another 100x the effort could compete fairly well, but nothing terribly close to "done".

Someone may reply to me with one. I'd have to look at it and analyze. But I know I'm not going to get dozens of citations of high-quality toolkits of, say, the calibre that I can put rich text widgets with high-quality multi-font unicode support and everything else I want out of such a widget, into a tree control with those rich text widgets as my leaves, and have a million node's worth of rich text controls because they can be lazy-loaded based on visibility, just to come up with one use case.