Well, I messed up with counting Haskell among low-level languages (I was thinking "low-level=functional purity" in this case). Fair to complain about that. But Ada is definitely low-level, and also faster than Go, has multi-tasking built in since '95, and was designed for large projects, so I'm still kind of dissatisfied with their answer. I gave Go a try several times, but it didn't look as if it had anything that I couldn't get as easily with Ada or Scheme.
From a modern language I'd expect the deficiencies of Ada fixed, a concurrent, incremental GC whenever I want it (but easy to switch off and also manual memory management and memory pools), and basically all dynamic and static features of past languages, where the compiler should automatically turn all dynamic types into static ones when it can prove it's safe. Sure that's a lot of work, but it's doable, especially with modern compiler tools like LLVM. I just don't understand why large corporations who have the money for R&D come up with such half-baked languages.