I think this should be renamed "Why many people are unhappy" - this isn't completely a trait of a millenial.
Bullshit. Our society runs on money. Not having enough money is a good reason not to be happy.
It is possible to have enough money based on your exoenses and those people are happier.
More people are unhappy because the economy is shitty.
Exactly. While this may be true for some - as you said "not having enough money is a good reason not to be happy." Status alone isn't the question - it's what "enough money" means. For some, that may mean enough to lord it over all of your friends - and for many it may mean enough to support your family and not ever worry about putting food on the table (along with a vacation and buying most of what you want, mostly whenever you want) - and for others it means enough money being able to do whatever they want whenever they want to do it, period. But saying it's just status alone is just crap.