Here is Mitch Flower Power performing the glitch on live TV in 2016 with Stephen Colbert: https://youtu.be/jvLwpnn1F4Y I believe Mitch was the first person to do this trick in RTA.
What the hell, he just pulled that off with all the distraction and people yelling, with all the stress, on a single try? How is that even possible, don't speedrunners do thousands of runs to get a win like this? Was it a real run? And Colbert was speaking and distracting him during some of the most important part of the run and cut off before even really showing his win. What a shame.
But once you are at this level, it is the other details that requires grinding:
The thing that sets the run from TFA apart from this run is the hammer bro manipulation that easily fails AND the luck of having good hammer bro movement (6% chance) after the manipulation is done.
Getting those two things on top of good execution is what requires thousands of tries for these top players.