I don't know whether you should be so sure that you're not mixing up cause and effect here. It might as well be that we have the economic apparatus because people naturally gravitate towards becoming fat and lazy. Or, most likely, both options are true to some degree.

> I know I'd never stop producing useful things.

I think few people are this driven.

I'm sure you believe this in good faith, but most human beings are not as driven and are not as good natured as you.

This is also why governments or any form or redistribution is inferior to a perfect market without human interference: you will always have bad apples stealing resources or being as inefficient as they can be. I know this because I'm a psychopath, I feel zero guilt or empathy and the thought that someone like me could be in a position of power is downright scary.