I agree with your logic, so far as it goes. However, there are, currently, just over eight billion humans in existence. If my quick, over-tired math is correct, that means only 34 people have to say no, until we run out of people to tie to the tracks. Assuming, at that point, the system collapses and nobody dies, I’d guess 34 people would refuse - might be the better choice.
Oh yeah. I was assuming an infinite series (somehow). Also, odds are good that out of 34 people, one of them would misunderstand the rules or be crazy enough to do it anyway for various reasons. I’d probably still do it.
Would you trust the entirety of human existence to be decided by 34 people? In my experience from watching reality TV, the last one always screws the rest over for their own benefit.
Imagine being the last one. You could singlehandedly wipe out half the global population. This would normally be a bad thing, and it is, but it would also make every surviver twice as rich, solve food scarcity and halve the pollution, perhaps even saving humanity from itself.
If that’s not enough, think about everyone now having double the amount of kittens and half the traffic on the roads.