There is no stabilization of the Japanese ethnic population in sight. With these trends I wonder how the island will change culturally in 100 or 200 years. I suspect we'll see them continue to open more and more to the west.
The rest of the West isn’t far behind. Only in Africa and a country or two in the Middle East is the birth rate above replacement rate.
Just a cursory Google search shows that countries like Mexico and the Philippines are way above the replacement rate as well so I don't think your comment is accurate.
Admittedly my comment was a result of a quick glance at the ourworldindata.org fertility map on a mobile device. I may have missed a country or two depending on the shading of the country.