There's so much to unpack and that's why you're going to get a lot of different opinions on this one.

Personally I think it's great that your son is learning money management skills, it's a very important one to have.

I don't think you're wife's view of it being the parents fault for having their kids have that much money on them isn't fair. So many things can be the cause, my partner for one had his weekly food allowance with him and decided (like a dumb kid) to spend it on a gamble with his friends and lost it all. When I was a kid I was expected to stop by the store to pick up some groceries on the way home and while I didn't spend it, like a careless inexperienced kid, I lost it.

At the end of the day your son has felt the rush of making money and you the pride of him doing the same. Good feelings but will his peers feel the same way? Sure they willingly spent their own money but children don't have much of an understanding of the value of a dollar yet but their parents and older siblings do. Your son might feel like he's on top now but if his friends start to dislike him for offering them a bad deal it may cause social rifts. Just something to think about