One thing that has struck me is that, in my opinion, smaller companies seem to get much more done per engineer than bigger ones This may be true but you are no

One thing that has struck me is that, in my opinion, smaller companies seem to get much more done per engineer than bigger ones This may be true but you are not comparing like with like. No small company is going to use agile methods to build a dam or an airliner or a nuclear power plant or a chip foundry. Small companies are adept at doing trivial things like websites. Big companies can take on projects longer than the career of any individual.