What is the true state of US economy? Could it be viable without the government debt growing at a crazy fast pace?
Every single economy that transitions from agriculture to industry experiences the same fall in birth rates. Having a lot of kids goes from being an insurance against elderly poverty to an insurmountable burden on your focus and finance. Most of the Chinese couples who have one child are happy to leave it from that.
How will China experience a baby boom any time soon? Why 3 years? Where's your evidence?
Look at deflation pre-WW1 and not that not only was this a period of growth, but also one where downturns were sometimes severe but over very quickly. You have the Panics of 18xx, but not any panics that last years.