A first look at Rust in the 6.1 kernel

This really isn't true. Depending what you're complaining about, Kconfig is twenty years old, not thirty. Roman Zippel rewrote it in 2002. The Makefiles were moved to their current declarative syntax around 2000. There are regular updates to the build system, including an active maintainer.

In summary, you have no idea what you're talking about.