I’ve seen some crazy stories on YouTube about people trading in cars they’re already underwater on just to finance an even more expensive one. I can’t understand why banks keep lending money for deals like that.
This has happened for as long as there has been car finance (i.e. practically since the dawn of private vehicle ownership), it's nothing new.
Given most folks cannot purchase a vehicle outright, the customer only really cares about the monthly payment, a sizeable amount of whom do not even understand the concept of being "underwater" on a trade in. The industry has always preyed upon the financial stupidity of most car buyers.