https://www.vox.com/2017/12/20/16772670/baby-boomers-millenn...
And roughly speaking, there are two ways society can turn current productivity into future support for retirees. The first is to forgo consumption of current production in exchange for a promise of future consumption of others production - this can either be implicit through a tax-and-distribute scheme, or directly implemented through debt. Retirement saving in general is the latter, and increased savings rate leads to savings gluts which cause cheap debt which forces the price of debt-financed goods up to make the market clear. This, in short, is why college is so expensive: every creditor needs to find a debtor, and Grandma bought up fixed-income products.
The second way to use current production is to leave easy-to-collect natural resources like oil in the ground, use current productivity to fund current consumption instead, and collect those resources later. Everything else is impractical on a society-wide scale.
True, there were minority voices clamoring that this would result in ruin, but to be fair there are still well regarded "smart" people who argue that the problem for millennials is that those people in charge just didn't do it ENOUGH.
I don't see a lot of evidence for this, except perhaps Reagan's program of deficit spending on an arms race to bankrupt the 'evil empire'. Maybe people should be forgiven for believing in the trickle-down lie once, but it's now simply a transfer of wealth scam.