I think "writing Rust in C++" so to speak means at least two distinctly different things, which are both important. The first thing is that, as an individual programmer, you're being disciplined with memory and thinking about who owns what. The second thing is that as a group of programmers (over time), you all agree about who owns what. There are a lot of ways to learn the first thing, but I'm not sure there are a lot of ways to accomplish the second thing in a large system.