I actually agree that on social issues, progressives dominate among the younger generation. That is true, and has always been true. It is also true that many will become more conservative as they get older. But the good news is this: not all of them do, and they don't go all the way back.
I have a friend at my second job who was homeschooled. I've never made the mistake of talking to him about religion, but I imagine he is a conservative Christian. I mentioned to him one time that I had recently gotten into DnD, something that was anathema to religious conservatives a generation ago. He smiled and said "awesome". Gay rights are another issue. I came from a very conservative small town, and I am shocked at just how many people I went to school with are progressive on that issue.
I suspect that the reason progressives are doing so well on social issues even when we're struggling in other areas is because of the Internet. Social conservatism depends on othering, which is difficult in the Internet age. When I was in church, I learned that Wiccans were more or less Satanists. It was the Internet which allowed me to realize what Wiccans actually are.
Now, I will agree that on economics, we are kind of moving to the right. One of my favorite coworkers is from the UK (he got married to a girl I went to high school with), and he has often told me "you guys need better healthcare". I often explain to him how American history was different than the history of various European nations, and how that shaped our political ideology. Of course, even in Europe, you see some far right figures rising up and wanting to privatize their health care systems. The truth is, there is no final goal of civilization. You get waxing and waning. You get a back and forth political process. If any progressives are ever feeling depressed about the course of America, just read Rapture Ready or any far right blog to see that the other side feels the same way.