Have you ever been in a situation where all you want is for it to be no more? I have, and while I haven't actually considered suicide, few thoughts have definitely ran through my mind wondering "what if I just didn't exist anymore so that I wouldn't be in this miserable situation" before quickly snapping out of it. Some people don't snap out of it and latch onto it while it slowly festers, and then ultimately it just happens on a particularly low day.
It could be possible that students in a high-stress, highly-competitive, financially-addled situation are unable to see the cold logic you've presented.
if you are dead, you don't have to deal with failure. For young kids who are easily impressionable - failure not being an option is forced into kids since kindergarten.