I like where this thread is headed. To expand on this idea, maybe we should demonstrate how diversity and inclusiveness can work in an operating system via language choices. Why stop at TCL and LUA? Or even scripting languages in general. Why not Go, Rust, Haskell and Scala too?
Hear me out. We can set up a raffle system so that each winner can write their winning tool in their language of choice. All the parallel development will even solve the "multi year effort" problem that was brought up by the original poster too. Nobody will mind having another 8 or 9 languages in the base system, right?