Not sure why you are being downvoted. It's at very least plausible. The reasons for much lower birth rates in western (and westernized) cultures are education,

Not sure why you are being downvoted. It's at very least plausible. The reasons for much lower birth rates in western (and westernized) cultures are education, security, and stability. Remove these and your primitive instincts like reproduction will start to dominate your life again (baby boomers as an example in US).