The big problem is comparing generations. A large chunk of people retiring today that had been living paycheck to paycheck, but a large chunk of them also have good pensions from work.
Pensions are a thing of the past. My company stopped doing them in 2007, 1 year after I was hired (so yes, I still have a pension, I'm waiting for the day I get a letter saying they are cancelling it and buying it out, which will really suck because it's heavily back-weighted).
Anyhow, people that retire 20 years from now are the ones that are in trouble. Pensions are toast, Social Security is not going to keep up with cost of living increases (and it could even go down especially if Trump cuts taxes....), and you can't rely on buying a house and having it's value go up at 10% a year so you're sitting on a $300,000 nest egg to sell and move into an apartment. So if you don't save you'll be stuck living off SS alone...which would not be fun.
I have a few friends in this boat. They don't even have retirement accounts, they live paycheck to paycheck with no buffer, they have consumer debt, they rent, and they have no pension. Literally in their mid 30s with negative net worth and no real assets. If you ask them about it they say something like "I can't afford to figure that out now, I'm sure I'll be fine"...It's possible they will get a windfall inheritance, but that depends on how their parents die (none of them are even remotely rich, so if they drop dead of a heart attack or car accident they'd have money, but if they move into a nursing home they'd probably get down to $0 net worth and have medicaid pay for the rest of their life).
So yea, long story short, I think people can get away with it now if they were even remotely successful, but I think 20 years from now we are in a LOT of trouble. A lot of trouble.