Of all the "impending crisis'" in the PRC, the "demographics" one ranks, what, 6th?
Pollution, a huge and growing middle class that's starting to want things the PRC can't deliver (like less pollution), no friends except Pakistan, paper military, fake economical numbers, mass corruption at all levels, state control of all the important industries and banks....probably several more I can't think of off the top of my head.
Well, it's a longer-term crisis, at least (after all, the missing children not born in 2018 wouldn't be in the workforce for another 18-25 years, and until then lower childcare costs are probably a boost to the economy overall), though a potentially more dangerous one than some others. But a more than 15% drop in fertility in a single year is... dramatic, to say the least.