I think an even bigger aspect of this is that C++ users are technical people who make technical decisions. If Rust is a better tool for them, they will switch. For a lot of scientific programmers, or even just a lot of general Python users, they don't necessarily choose Python because they know 20 languages and think Python is the best tool for the job. A lot of people use Python because... they use Python and it's what they were taught. That's a much harder audience to go to and say "would you change to this technically better language?". Most just say "I'm not really a programmer, I'm a researcher/scientist/etc. so I shouldn't spend time learning more programming", and that makes it fairly difficult.