As others have written, it can. Dart/Flutter is clearly further along. The main non-technical reason for this is that Flutter is the single blessed UI toolkit

As others have written, it can. Dart/Flutter is clearly further along. The main non-technical reason for this is that Flutter is the single blessed UI toolkit for Dart, whereas Rust instead relies on the creative chaos of multiple competing and/or overlapping open source projects. The Dart approach concentrates effort and removes the burdens of choice and intergration from app developers; the Rust approach has more potential for arriving at novel solutions, and is less likely to get trapped by top-down decisions. It's all pretty promising, and great to have some alternatives to the rather creaky old toolkits we have. I personally think web tech will continue to be a strong contender or many multiplatform apps (for which - Rust has Tauri).