May be I misunderstood something, but dropping dependency on glibc doesn't imply static linking.
Of course reusing C library means linking with libc and reusing C++ library means linking with libstdc++. But in a long perspective those libraries should be implemented with Rust to have all advantages of the better language.
And using rust without libc might help with some embedded use-cases, where people don't want to put unnecessary stuff. Rust as a 0-cost systems language theoretically could be used there instead of C.
Of course reusing C library means linking with libc and reusing C++ library means linking with libstdc++. But in a long perspective those libraries should be implemented with Rust to have all advantages of the better language.
And using rust without libc might help with some embedded use-cases, where people don't want to put unnecessary stuff. Rust as a 0-cost systems language theoretically could be used there instead of C.