Inside China's push for more marriages and children (youtube.com)
Youth aren't marrying.
Youth unemployment (rising), housing costs (rising), weddings still expensive, people living in the cities more, have pets and careers, choice not forced to marry.
China's government is offering marriage bonuses (cities offer cash or vouchers for furnture, paid work leave), offering marriage vows and drone shows on social media in nice looking locations. Basically everyone doubts this will have any effect, although even a small effect could be meaningful.
During the one child policy, Chinese citizens who had more children were publicly shamed as unpatriotic, punished, fines, sometimes jail. ... In the past, people married and had children partially to feel more secure.