You are correct for the causes. However, Asian countries like Japan, China and SOuth Korea have seen an even quicker drop in birth rates. This has to do with the phenomena of single motherhood in western countries, where it is more accepted as compared to Asian countries.

 42 percent of kids in the US and 25 percent in Canada are born to single mothers, where the father is not present. These kids tend to drop out of school, become minimum wage workers or criminals.