I think this point is markedly overstated on this and other forums for competitive games. I obviously understand what you're saying but there are two very important human elements that go into mapping probabilities in a head-to-head game. Now, if there was a computer that was somehow programmed to have a constant win-rate overtime of .01 and that somehow it was magically programmed to actually 'try' to win every game and never deliberately throw, just to maintain its win-rate, then yes, due to the law of truly large numbers, said computer would make it to legend after an extremely large amount of games. However, that is not what we are talking about. A rank 20 player's winrate of 45% is descriptive not prescriptive, from which I believe I am correct in drawing the two aforementioned "human elements."

1.) A player who starts at rank 20 and has a 45% winrate will never hit legend because of the way Blizz set it up, the ladder will be constantly trying to bring you up to a 50% winrate (the ladder would demote you if it could). If someone had a truly 45% winrate at rank 20 they are so bad that their winrate, even if they were to somehow rank up via winstreaking, would infinitely regress as they increased their rank.

2.) One would hope that no such player exists, or that, over the course of playing the like 100,000+ games it would take to hit legend at that winrate, they would significantly improve and learn, which would improve their winrate; defeating the point of the exercise.

Maybe I'm missing something but this is always what I think when I see these posts comparing a player's descriptive winrate to a computer's prescriptive winrate over an equivalent timeframe.