Europe and the new old age

Europe seems to be the poster child for the idea all prosperous democracies will eventually encounter economic senility as their populations age.  Japan is already there and China may well be next.  What does it mean when the reproductive rate of a country falls below the replacement rate of approximately 2 children per woman?  The relentless rise of the cost of raising children saps the desire of couples to commit to years of two earners working full time to attain the same standard of living previous generations achieved with a single earner.  Day care, housing, college costs and other out of pocket expenses make it less and less enticing.  France, the anti-Christ to many on the right has bucked the trend by basically subsidizing reproduction.  Generous benefits for young couples, including child care and education subsidies makes raising children attractive again.  People really love the warmth and love a family can generate.  The trick is to make it affordable.  If we don't, the aging population will be cared for by foreigners and the new blood essential to keep democracy vibrant will gradually disappear.