The strong criticism Rust got in this area is being poorly suited for rapid throwaway prototyping. I think that's fair — slow compile times and language's focus on writing things properly on the first try are the opposite of what you want when trying out random ideas and seeing what sticks. I think that may be fixable. Partly it's a skill issue (with enough experience, you can cut corners when you known which ones to cut). Partly it could be improved by tooling for hot reloading, and perhaps a scripting language integrated with Rust.

In Bevy in particular almost everything happens through ECS, and the ECS has a Reflection API, so you can hook it up to whatever you want, and manipulate it from any language.

I also wonder what about the rest of the game development lifecycle. Games are taking many years to develop, and not all of that is quick exploration. The more of the game starts taking shape, the more you actually need stuff to work. You need ability to refactor, polish, and extend the implementation without breaking things. You need to be fixing gameplay bugs, not wasting time on hard-to-reproduce crashes.