> If you prefer, Rust tooling is still quite far behind from languages like Kotlin and Scala

I'm not sure that's true, at least when it comes to specifically build tooling. I'd say Cargo is far ahead of Gradle, Ant, or worst of all SBT, and probably even slightly ahead of Maven (which never really reached critical mass in the Kotlin or Scala ecosystems sadly).

You are missing the IDE capabilities, maturity of GUI frameworks, a full OS that 80% of the world uses,... the whole tooling package.

"build tools" does not normally refer to those things.

It does for me, using IDEs with Borland languages for MS-DOS.

It is about the whole package.