At some level, even the physicality evens out (it's really about stamina), and boat speed and mental toughness tend to determine the winner. An Olympian told me this (because I'm not at that level either, LOL).

I have been to (and observed online) a large number of major regattas where at least 10 teams could win / have won prior major events. At some point, luck definitely can't hurt...

Mike