Fuzzing has found plenty of security vulnerabilities, to be sure, but I'm skeptical that it makes static analysis obsolete. Even if it were possible to write a theoretical fuzzer that would find every possible security vulnerability, it'd still be a whole lot cheaper, and easier, to just have a tool that enforces that you write the code correctly in the first place than to spend time writing it in an unsafe language and then developing a world-class fuzzer to find all the vulnerabilities.