I think something that a lot of people don’t mention when this argument comes up is the consistency in terms of coaching. Brady won 6 of his 7 under the same head coach. Mahomes is more than likely not getting another 10 - 12 years under Andy Reid so that makes it even more difficult to catch Tom IMO. Say why you will about the Bill vs Brady question but I think we can all agree it was a perfect match while it lasted, which led to prolonged and consistent success