FWIW that's not a true statement. Large companies have roles and vacancies where there are expectation and existing code to maintain.
E.g. when I was at FB I joined a C++ team while having written about 200 lines of C++ before in my life — we also had proper C++ experts in the team, and they cared more about experience in the problem domain. All of these conversations were held _after_ I was hired though — the pipeline is a mixture of hiring experts for specific positions and "hire people that seem good enough, and let them find their own teams"