Does he really only do Battle For Bikini Bottom runs? He plays nothing else? Why doesn't he try SpongeBob: The Movie Game for new runs or something? It's basically a sequel that runs on the same game engine. Or just try different 3D platformers if that's your style of game. I would imagine raging at the same SpongeBob game all the time would get really tiresome fast. He already has the world record. What is he trying to accomplish? Speedrunning ain't worth killing yourself over.
He wouldn't have a thread here if he was thinking as rationally as you would like him to. Since his goal is to be "THE Spongebob BfBB Guy" and to keep lowering the time it takes to finish the game, he said multiple times already in some heated rants that he cannot quit playing the game even for a week, since it will fuck up his muscle memory for 1-frame tricks etc.
That's also why he gets very angry when a controllerbreaks. Not only does a replacement cost like 80 dollars or something iirc, he has to "break in" the new controller to get a feeling for it or something. It's an endless cycle of suffering.
But I liked your comparison to BossManJack, I feel that's in essence what most speedruns boil down to nowadays, hoping for that one run where you are in the zone, or hoping for good RNG. I think the most soul-sucking speedrun I have informed myself about was Yu-Gi-Oh Forbidden Memories.
Got the wrong starter deck? Restart
Got some bad drops from duels? Restart
Enemy got his strongest monster onto the board on the first round? Restart
Bricked hand in the final 6? Restart