The 2-6 weeks figure seems optimistic to me. I think it’s easy to underestimate how long it takes to switch languages and operate at a high level of productivity in the new language. Yes, switching languages is much easier than learning to program. Yes, I would rather hire a proficient programmer who doesn’t know the language than a mediocre programmer who does. But no, I don’t think that 6 weeks is enough for most people to get their Rust skills to a professional level.