My sense is they’ll be counting on the majority of Millenials and Gen-Zers being too young to worry about retirement. Given the rise of the gig economy and part-time work replacing traditional full-time work for people now under 40, they may not be so sensitive to how much they paid in.
I also can’t rule out the possibility that the feds cut the benefits in the process of eliminating all social welfare programmes permanently to fund a neoliberal version of a UBI. Automation and increased productivity is only going to continue to reduce employment opportunities in the 10-year-plus time frame.
You make a good point about retirement age. The first step will probably be to raise the full benefits age from 70 to 75 and the early start date from 62 to 67 or 68, supposedly in the name of longer lifespans and working years. However the manage it, I’ve been operating for many years on the assumption that the duopoly parties’ establishments will be more than willing to screw over a demographic that lacks electoral clout if the timing and conditions line up.