What supports that statement exactly? If you split your big projects into crates it would recompile pretty fast. C++ can also take ages to compile (eg. compiling Firefox from scratch). Keeping your code modular to get decent compile times seems like a win win.
I never compile C++ projects from scratch like I am forced to do with Rust.
The only code I compile from scratch in C++ is the code I write myself, everything else is available as binary libraries, something that cargo doesn't do, and it is not part of the near future roadmap, if ever.
Then, after compiled, most of the stuff lands on the VC++ metadata files, so incremental compilation and linking cuts even more time from the usual edit-compile-debug workflow.
Interesting, is this common on windows? On Linux I've never seen precompiled C++ libraries (at least not these with templates) back when I compiled stuff more often (read: back when I used gentoo). Do g++ and clang++ support precompiled libraries in the general case? I suppose C++ modules might make it more common anyway, but I don't see why rust couldn't do it if they ever prioritize it.
The distro takes care of it and you just yum / apt-get / whatever the lib and then compile the code you typed in. Template libs will slow down your compile times but there is still a lib boost.so etc sitting around.