I would be surprised if more than 5% of people who do Introductory EA fellowships make a high impact career change.
Do you have a sense of the fraction of people who do introductory fellowships, then make some attempt at a high impact career change? A mundane way for this 5% to happen would be if lots of people apply to a bunch of jobs or degree programs, some of which are high impact, then go with something lower impact before getting an offer for anything high impact.
I think it's reasonable to go either way on Starcraft. It's true that the version of Alphastar from three years ago were not beating the best humans more than half the time, and they did not take screen pixels as inputs.
But those models were substantially inhibited in their actions per minute, because computers that can beat humans by being fast are boring. Given that the version of Alphastar that beat MaNa was already throttled (albeit not in the right way to play like a human), I don't see why an AI with no APM restrictions couldn't beat the best humans. And I don't see any particular reason you couldn't train an image classifier to get from screen pixels to Alphastar's inputs.
So I think this mostly comes down to whether you think it was implied in the prediction that a realistic APM limit was implied, and what your bar is for "feasible".