There is no reason that serious things written in Rust can‘t coexist with app-y stuff in swift.
Seriously, I think we all would benefit enormously from some consolidation, especially on such a great foundation like Rust. Think investments like: compiler-optimizations like V8, portability like C, enterprise grade tooling like Java, productive libraries like Ruby, datascience libs like python, ... it would be great to have all of this in one coherent package.
Why? Instead of glueing together brittle and fragile things where the moving parts break within weeks, reinventing the wheel, we could finally focus on the actual things to build. Bonuspoints for Rust: every other techstack can leverage/profit directly, like when binding C stuff.
Everyone still can innovate like the past decades, languages and libs will be re-explored and reinvented and so on, but, really, a solid baseline would be a dream