I can see how some of them feel that way, it's not wanting $15 to flip burgers either or getting a niche degree and demanding $100k starting salary.
A larger percentage of wealth has been moved into a smaller percentage of people in their life, so there is less money to go around in the larger percentage. Almost like the gilded age at the beginning on the last century, I have a feeling I this continues your going to see a lot more Bernsters, they will get in charge and government will be involved (and not in a good way).
Wages have been stagnated for decades, pretty hard just to look at historic wages and see $18-20/hr union jobs from the 70's in smaller Midwest cities. (Caterpillar in my hometown of 27,000 people paid $18/hr for a production welder in 1979). Housing is expensive for many, you move to a new town out of college and over half your take home pay is paying rent, doesn't leave a whole lot of money at the end of the month. Many places it is hard to live the American dream without both spouses working average jobs.
Trade jobs until recently was shunned as a bad, you need to go to college. Apprenticeship programs are not very common (appears they are making a comeback), or you go to trade school for 2-3 years and hope for a job when you're done. etc. etc.
If I was 18-25, I wouldn't be seeing a rosy picture either. Expense of college, health insurance costs, trying to make rent, car payment, etc.