maybe not 2100 even

Chinese government does not seem to agree with you, considering its:

• Pro natal policies
• Heavy research into automation being sold as "to fill in labour gaps" (even though the gig work is skyrocketing)
• Retirement age reforms increasing the retirement age

Chinese universities also do not agree with your flippant attitude and are literally alarmist about it:

Tsinghua projections (that accurately predicted peak of population) show halving the population (and that > 50% will be people over retirement age) by the year 2100: https://www.dess.tsinghua.edu.cn/en/info/1226/2472.htm

On the other hand the dude who was saying something about collapsing in 3 years also didn't knew what he was talking about.