Ask HN: If All Jobs Are Automated, Who Pays for Products/Services?

Seriously, is there any answer to that? Is it a situation where unless UBI is implemented, the entire economy crashes due to having no one able to pay for anything? Or is there some other way to make an economy function if no one has the money to afford anything and everything's been entirely automated?

I'm just curious, and I'm interested if there are any blog posts, academic papers, etc explaining what would happen here.