For comparison, 50K hands is a standard length for heads up matches between pros, with the understanding that even then the best player is not guaranteed to win. In live play, you'd be looking at 50-100 hands per hour.
It's true that with a greater skill gap you'd need less time, but you'd still be looking at thousands of hands if you wanted something like 95% confidence that the better player was up.
A competent but not great player has a chance of beating a pro in one session, but it's definitely pretty slim.
For every tournament you make a big score, you crash out of 5 and get min payout on a few more.
Many of the biggest names in poker have been the biggest losers in a given calendar period. For example, Gus Hansen and Daniel Negreanu are two of the biggest winners of all time yet also have some of the biggest documented losses...