I have no business related to Rust, but after reading a few articles from this author, I tend to think that his approach to GUI toolkit design is deeply flawed.
He is undoubtedly highly knowledgeable about the subject, but this knowledge may be a curse in his case.
A mix of second system syndrome and Architecture Astronaut, trying to satisfy too many constraints can be a deadlock.
I think the sensible approach is starting with a Minimum Viable Product, cutting some corners and consciously making tradeoffs. And if success comes, then try to organically grow from there.
A more scrappy approach is what I'm trying to do with my library, rui [1]. Just get something out there. Also, it's really in service of my (already released) app, as opposed to trying to be a successful open source project. If others happen to like it, great!
That said, I think Druid is a good Minimum Viable Product. I just needed GPU acceleration for my app, and wanted something closer to SwiftUI, which I'm used to.