There's also good reasons that immediate mode GUIs are largely only ever used by games, they are absolutely terrible for regular UI needs. Since Rust gaming is still largely non-existent, it's hardly surprising that things like 'egui' are similarly struggling. That doesn't (or shouldn't) be any reflection on whether or not Rust GUIs as a whole are struggling.

Unless the Rust ecosystem made the easily predicted terrible choice of rallying behind immediate mode GUIs for generic UIs...