> "Why would you need BI if that existed in the first place? Then people would have the discipline to not work shitty jobs and strong competition would provide them the work they want! What has BI solved, then?"

The desire to eat trumps the desire for a better job. If you tie people's choices to their need to survive, you are going to interfere with what people would choose that serves their best interests. Amongst other things, UBI tackles this issue.