Chinese dont even have two children even with this policy now, the birth rates dropped even more since the once Child policy got lifted, this proves that the goverments policies wont have a positive effect on birth rates.
The biggest problem for China is that a whole generation of single childs grew up, the problem with this is that those got spoiled so much that many see children as a burden which is not worth taking.
Fixing Chinas demographic problem is harder than you imagine, its not like the goverment can turn on a switch and people will start making children.
In my opinion the demographic problem is the biggest challenge China faces before any foreign enemy, even before environmental problems, you guys should shift your focus to the real problems and reset your priorities.