Stein got 0.6 million votes. Over a hundred million stayed at home. I sincerely doubt that each of those hundred million is a dyed-in-the-wool anti-electoralist, so why focus on the "Not left enough" people? They had no effect on the election one way or another, just like they kept telling you. Your problem is that the majority of people in this country are completely alienated from politics. If you continue to focus on the left to the exclusion of the Democrats' very real shortcomings, if you continue to ignore DNC's failure to offer a winning platform to everyday people, then you are damning us all to an eternity of the current moment.
response
Thanks for the catch! Once I noticed that the probability of winning on the initial flip was the difference between the two, I stopped thinking about the other terms...
I read the other answers in the thread, and I definitely would have gotten this wrong without that. This answer stands a chance at least
Independence
A and C are independent, A and B are not. Since you have a chance to win on turn 4 that you do not have on turn 1, P(A|B) = 1/2 + 1/16 + 1/64... = 7/12 != P(A). Conversely, P(A|C) = 1/4 + 1/16 + 1/64... = 1/3 = P(A)