Quine has that famous saying, "Philosophy of science is philosophy enough." While it is quite a strong pronouncement, it isn't one that seemed to impart a great deal of influence on Quine's own writing. He didn't write much about philosophy of science. He often wrote that science should have pride of place in our worldviews, but there isn't much philosophy of science proper. I think the closest he gets is discussing the relation of theory and evidence, which is certainly a bit of philosophy of science. It is sort of like the people that say philosophers should engage in naturalized epistemology, e.g. my hero Van, but don't include long discussions of psychological literature or cite any psychological findings. Gesturing at Psychology, with a capitol 'P', is not enough I think. Davidson, while not buying into this "philosophy enough" business, did "dirty" his hands with some empirical research in decision theory. He published the results in a book with Pat Suppes. It's understandable why one would want to stay away from the research and stick to the pronouncements. The former are frustrating and a huge time sink.