I could be wrong, but I'd bet money that you didn't have a pin hole. Just as you said that you don't know why it lasted this long, sounds like even you have doubts.
The leak that you didn't fix, can be very deceptive because the oil goes everywhere anyway. The oil tends to run over to that side when the bike is on the side stand too.
Of course, this could be a first among the thousands of oil leak posts that we've discussed. Yet, I bet that you didn't need a new head gasket, either.
Did you say the pin hole was in this area?