I'd like to point out that those kinds of insane speed runs aren't purely the product of playing at low speed, they're also the product of being able to reset time and try again.

(or do you really think that if, on the final level, after months of ultra-slow play, if the player realizes that they're going to miss a jump and die that they'll start all over again)

Speed isn't everything, if a chimp had 2 years to ponder every 2 minutes its still unlikely to be able to outsmart the zookeepers. more likely it would just start to lose track of why it was doing anything.

You can leave a genetic algorithm running for a million generations but you'll probably not gain anything notable after a certain point because it will get caught in local minima. There's plenty of humans who just end up in a loop if left with a problem for a long time.