Blaze is, Numba is a JIT compiler to LLVM. You can write numpy functions and JIT/Multithread them with just a decorator and zero to few code changes. Blaze makes this transparent to the user, chunks backends, provide out of core array object, abstract expressions etc.
Numba + Blaze boosts numerical python to speeds on par with or greater than julia, with additional out of core, delayed expression and multiple backend capabilities that Julia currently does not have.
This might stem the tide for a while... Then we have pyston which maintains C api compatibility.