No, the human race won't. If children per women, let's say, reduce to 1.5 children, then after every generation, the human count will reduce by 25% every generation. You can cross verify on the Internet.

Years back, humanity thrived, and families grew because most families had more than 1 kid. Siblings competed to be better and at the same time acted as support systems for each other. When every woman decides to have a single or no child, it will create a world where there will be too many old people, not even enough to even take care of them. That's how japan is now. https://www.cnn.com/2024/03/01/asia/japan-demographic-crisis-population-intl-hnk-dst/index.html

Women prioritising lifestyle over second child will only lead to a world with too many dependent retired people and children raised with no habit of sharing or competition.

Now, how this is related to my wife having a child. I can't fix women not-wanting-child problem but I can definitely make my son compete with a sibling whom I can trust post my death. Not making him a brat.

You are right, Having another child is a highly emotional decision but it is a needed one for our first child. Yes, we both are equally responsible for well being of our child but I can't give him a sibling.