I agree with what you say somewhat - that generally millennials parents didn't teach them how to properly manage money - and they spend too much because of it. However, it's not the only contributing factor to the bullshit we are seeing happen now. Millenials, however, do have more information about budgeting than their parents had, so they should fix that.
BUT, How do you explain the increase of worker efficiency without an equal raise in pay? We're doing more work than ever and getting paid the same or less. Don't forget too that even our education has gotten inflated - colleges adding more and more bullshit filler courses to degrees to force people to pay even more for a shittier education. Meanwhile, CEO's are making 300X - 400X more money than their lowest paid employee. When our grandparents were going to school, that number was around 25x. Not the same situation.
So, yes... young people these days spend too much. However, there is SO MANY CONTRIBUTING FACTORS that to blame them exclusively without checking the other powers and institutions is short-sighted if not malicious. If you're one of those people that never blame the rich, you're sleeping at the wheel.