As a Python dev getting into more Rust development, I'm surprised whenever I hear of this as a progression towards better tools, rather than a way of adding new tools into my belt.

Django/Flask are great tools for spinning up a CRUD application with authentication/authorization, API endpoints, and a template language if I don't want to build out a React or Vue SPA.

Rust is a great language that's opened me to new domains of programming, and also gives me the ability to write more performant, hardened API endpoints at the expense of productivity in hours (this gap will definitely shrink as I get better and as rust frameworks mature, but I'd be surprised if it went away entirely)

If a developer views a suite of tools they know very well as "something they used to use", they're more likely to make future architectural decisions based on incorrectly viewing framework-powered python as a relic of the past, rather than a viable (and often preferred, if hours of work are factored in) alternative.