Japan is committing suicide because it’s people can’t be bothered to have children. Same thing is happening in just about every 1st world country. It’s especially bad in Japan though, because immigration for all practical purposes, does not exist there.
Also, remember that Japan does not have a Christian heritage that specifically values life. As for the barren state of the 1st world, some quotes from TR are relevant here:
On motherhood as the true source of progress, Teddy Roosevelt said:
“A more supreme instance of unselfishness than is afforded by motherhood cannot be imagined.”
Before an audience of liberal Christian theologians in 1911, he said:
“If you do not believe in your own stock enough to see the stock kept up, then you are not good Americans, you are not patriots, and ... I for one shall not mourn your extinction; and in such event I shall welcome the advent of a new race that will take your place, because you wil have shown that you are not fit to cumber the ground.”
On the centrality of the child-rich family to the very existence of the American nation:
“It is in the life of the family, upon which in the last analysis the whole welfare of the nation rests....The nation is nothing but the aggregate of the families within its borders.”
On parenthood:
“No other success in life, not being President, or being wealthy, or going to college, or anything else, comes up to the success of the man and woman who can feel that they have done their duty and that their children and grandchildren rise up to call them blessed.”
On out-of-wedlock birth versus practiced sterility:
“After all, such a vice may be compatible with a nation’s continuing to live, and while there is life, even a life marred by wrong practices, there is a chance of reform.
In another place, on the same subject:
“...[W]hile there is life, there is hope, whereas nothing can be done with the dead.”
On the behavior of 90% of those who practice birth control:
“[It is derived] from viciousness, coldness, shallow-heartedness, self-indulgence, or mere failure to appreciate aright the difference between the all-important and the unimportant.”