Yes, of course we can still quibble with the assumptions (like the OP does in some cases), which is why I say “moderate evidence” rather than “completely watertight proof”, but given how natural the assumptions are, the evidence is good.
Completeness is arguably not natural (see e.g. Aumann, 1962; Bradley, 2017, §11.5). In particular, I think it is clearly not a requirement of rationality.
Completeness is arguably not natural (see e.g. Aumann, 1962; Bradley, 2017, §11.5). In particular, I think it is clearly not a requirement of rationality.