One thing might be, Yeonmin has been living his life faithfully. Always working hard and doing his best to overcome his hardships through genuine effort. Taeseo is demeaning all the hard work and efforts he has put in...that's what hurt him ig? He was always good at studies but now people think he is just a spoiled, sponsored kid who has been getting all the good grades through connections. Its definitely a matter of pride. But yeah irl I agree with you, I would have sucked him dry if I was in Yeonmin's position.
Well, he has practically nothing to lose. A lot of people seem to see him as a helpless pushover but he really isn’t. And on that note, just because he isn’t a pushover doesn’t mean he’s the kind of character that would ever even WANT to turn thw situation around making mr yeon beg. Yeomin is an extremely strong and kind character but he’d rather suffer than be reliant on someone else. Did he love Mr yeon? Yes. But that doesn’t mean he trusted him. Throughout the story he is naive and innocent, yet you have to remember the hell he’d went through to end up still on his feet, working these jobs with minimal mistakes, while being top of his classes. Yeomin is an independent character. And that’s why hes so loved. Also no hate just explaining how I read thw story!! Hope Mr yeon grovels like a dog

But genuinely asking, where is he trying to escape to exactly, no money no family, he could literally turn this whole situation around and let that mf beg. He could use that mf to his own advantage and by making him bankrupt since he loves throwing money at everything. Some author needs to start thinking outside the box sometimes instead of repeatable story everytime. I mean they're still gonna end up with each anyway like kim Dan and his lover.