The honest truth (and I’m a millennial) is that so many of them piss away whatever extra money they have on Starbucks, figurines, avocado toast (lol), expensive hotel rooms, etc. They live only for the now. Also, they are too arrogant to ask for advice, but also lack the ambition to figure out things by themselves. They just don’t even try.
Don’t forget their electronic gizmos and devices. I read in some finace magazine that millennials consider devices more desirable than cars.