What I don’t understand about people like this is the wasting of all your younger years for some hypothetical future of leisure when you could die in your sleep today. Like, what’s the point?

It's just a matter of having accepted and internalised what the point is of you being born and alive is as told by the ruling class. You are supposed to work your bones off, generating surplus value for your masters, and be miserable in the off time, unable to imagine a better world.