Well, our lifestyle just isn't sustainable I think...fundamentally.
We can't only be producing in the economy for 35 years of our lives and then expect to retire and live in luxury (1-22 years and then retirement to death, say 15-20 years there). It's just not sustainable, not when the rest of the world is willing to work for so much less money and do the same thing. They're starving, so they're willing to work 12 hour days. We're just going to have to suck it up and keep working till we're no longer able (till like 70-75), and then move in with your children-- the way it's worked for all of history until now.
So, people need to keep working (delay SS until 75 or whatever the avg life expectancy is-- used to be 65 that's why SS started at 65), and just be content with less-- such as living with your children if you can't afford your own house.
There's really no way out of this, it's either inflation with the Federal Reserve buying all the US Treasuries (result will be cost of living goes way up until the SS payments aren't anything at all anymore-- ie barely cover food if even that), or the gov't axing benefits for the old people-- the end result is the same, they end up with less. The working population won't put up with another Income Tax (which is what this will turn into), they'd rather have the money and mom/dad just have to live with them.
I'm not really sure what world you live in where SS is living in luxury. In no universe are monthly SS checks considered luxirious, that's just a fundamental misunderstanding on your part. You're also making claims about how old folks have lived with their kids "for all of history" as if anyone who has actually looked into the history of that statement could possibly corroborate it. Not since the early 19th century have parents and their children consistently lived together; once families started having fewer babies (because they didn't need/want kids to subsist on farmland any longer, so children left earlier and parents were forced to fend for themselves in their old age, helping to lead to the idea of having to save money in banks over one's lifetime), have children and parents lived together in the elder's retirement in any significant numbers. We're talking 200 years ago.
Your statements also ignore the reality that other countries are already successful at doing this; plenty of other countries have workers that work for less than 35 years (like France, like Britain) who retire with very good benefits and can do so for 20+ years.
The country has been putting up with it since the 19th century, and the numbers say it's not really difficult to sustain with a combination of more people, more economic growth, more taxes and, yes, more inflation. You're going to have to get over the idea that inflation is bad, because it's a very sensible way to grow an economy in moderate amounts and far superior to letting dollars deflate which is, of course, the only alternative.