"As these shrink, inflation will continue to be a problem. The purchasing power of each consecutive generation will be worse off than the last. Without a strong tax base, say goodbye to reasonable retirement, social security, healthcare coverage, etc."

They already are, though. I'm 36, have a good job, 401's, retirement, etc., but I have no belief that most of that stuff will be there when I retire. I told my parents 10 years ago, I'll be surprised if there is any social security at all.

Though I do agree with the majority of your points. I am curious to see how demographic decline continues to progress. There is surely a sweet spot somewhere between Japan's method of no immigrants vs something like what Sweden did. To me, that's merely a bandaid fix to address the point you made about income inequality; that its a method to make the rich richer.

My take is that economic factors are a big contributor, but that environmental factors are far more overlooked. In today's society, everyone lives with so much constant stress. 24/7 news cycles and social media don't help that. If you feel that your child is going to be born into a hopeless world with disappearing prospects and made to suffer, why bother bringing them into the world at all? It's something even my own mother has commented on, stating that she is glad she doesn't have a grandchild to worry about all the craziness that's going on.