They will do this for something called money. During this entire process of 80,000 hours worked, 99.9% of people will never take even 15 minutes to try and understand what money is - the very thing they have given their life to. I find this beyond fascinating, and it is why the basics of modern money mechanics, the simple structure of how our current monetary system works, is something I repeatedly come back to on this site.
The following video provides an in depth look at this process told through cartoon story form making it easier to understand for someone new to the topic.