> Very much so once you compare it to how quickly C++

C++ came out in 1985 and competed with C, COBOL, Pascal and FORTRAN. It was an overall improvement than those and therefore there is a legit reason for it to take off.

> how many of them end up using it (and to what extent) you see it's not like it's been with languages that ended up achieving real popularity

I assume many places that have a huge codebase in C++ would just do a port to Rust. That would almost always cause problems but for greenfield projects it's a no brainer IMO.