My grandmother can still, to this day, recount living in an apartment with no furniture except a mattress, with my grandfather who was employed as an engineer in New York. It took, by her estimate, about two years to have enough furniture before she was willing to invite over any sorts of company.
Today you can furnish an apartment reasonably with about a months worth of wages. I know this because I helped take a friend who makes a bit over minimum wage to IKEA to get all their furniture for an apartment they moved into.
The myth of decline is that - a myth. The economy is better then it has been in decades, violence is at an all time low, and jobs are widely available in many areas of the country.
I have friends who complain about the economy "being destroyed", who max out credit cards to buy brand new cars and buy expensive home theaters. I have one friend who despite making six figures a year, took a predatory payday loan because she had spent her wages on expensive unused tools.
That's not to blame "millennials" anymore than to blame any other generation. Bad financial choices have existed since the dawn of human history, but in many cases today they are choices, not pre-supposed economic outcomes. We can help correct that by teaching good finance skills (budgeting, doing things yourself instead of hiring people, focusing on cheaper hobbies, etc).