Old people will be gone one day, some men will have to find wives abroad or live single by choice till they die. Automation and new tech will replace cheap labors.
It is India and other similar demographic wise countries that need to beware of their future. They will have to provide jobs for tens of millions of new workers every year just when automation is about to take off. Not to mention they also have to provide better living standards. While the pie grow bigger, the number of people who demand for the share of the pie is also grow bigger, can the pie grow bigger and faster than the number of people? While in China the pie can grow bigger while the population is shrinking.