Yes, overall birth rates might be going down, but that doesn't mean that there will be fewer people where OP lives. Chances are the rest of the world wants to live where OP lives. I don't see Australian house prices going down any time soon, and I don't see these trends reverse in my lifetime. And I'm not even that old!
[1] https://www.theguardian.com/australia-news/2024/mar/21/migra...