Unless you believe that guy cheated, the course was pretty much spot on. As someone pointed out he swam 51 in hawaii on a slowish year there, so what you would expect from a guy at altitude in fresh water. He probably can swim 47 to 48 under ideal conditions.
As to the rest, I believe i explained it. Virtually all people suck at altitude swimming, even experienced swimmers. Unless you absolutely know the score, your pace you should be swimming, and you are acclimated, you are going to lose time. Even the leader lost time, but he was apparently ready to do the high swim. And the absence of pros also takes away a lot of the sub hour swims. I would say that even well trained swimmers in the sub hour range would lose between 3 to 7 minutes just from the altitude, some a lot more. Go back and look at the amount of people the broke 1;06 or so, and see if that doesn't come closer to the number that usually break an hour(in a non wetsuit swim of course)
As to the rest, I believe i explained it. Virtually all people suck at altitude swimming, even experienced swimmers. Unless you absolutely know the score, your pace you should be swimming, and you are acclimated, you are going to lose time. Even the leader lost time, but he was apparently ready to do the high swim. And the absence of pros also takes away a lot of the sub hour swims. I would say that even well trained swimmers in the sub hour range would lose between 3 to 7 minutes just from the altitude, some a lot more. Go back and look at the amount of people the broke 1;06 or so, and see if that doesn't come closer to the number that usually break an hour(in a non wetsuit swim of course)