Its cross-platform support (not just for using but also for building it) is not there yet, and it is quite huge and unstandardized with only one full implementation. I'd agree the last part will change with age, but given the frequent large changes and feature additions I am afraid it will be harder and harder and it is simply too complex and fast-moving for many low-level applications. It is closer to C++ than C in my eyes. I'd be happy seeing it replace C++ though for its memory safety benefits!