I think people like medium-size cities in general. Kumamoto in particular is attractive, is decently convenient, good climate, and while Kyushu in general has a conservative image ("Kyushu danshi") it has been changing for the better.
But given all of that, Tokyo basically has its own economy, it's own rules, and isn't just "big", it works differently enough that people's choice isn't on which city, but whether they live in the Tokyo area or not.
For instance if you're gay, the Tokyo administration will give you an equal marital status. Kids's private school tuitions are partly covered (they're ragingly expensive in the first place, but you get prime access to very competitive schools). Health care will usually be completely free for kids. Remote working is usually treated differently if you're vaguely in the area or if you need a flight, living in the mountains in Okutama will land a better deal that living in Shizuoka, even if commute wise it's probably the same.
This is of course an issue, especially as national policies need to fit both worlds which is a pretty hard (the whole discourse on the spouse wage limit is basically centered on this divide)
But given all of that, Tokyo basically has its own economy, it's own rules, and isn't just "big", it works differently enough that people's choice isn't on which city, but whether they live in the Tokyo area or not.
For instance if you're gay, the Tokyo administration will give you an equal marital status. Kids's private school tuitions are partly covered (they're ragingly expensive in the first place, but you get prime access to very competitive schools). Health care will usually be completely free for kids. Remote working is usually treated differently if you're vaguely in the area or if you need a flight, living in the mountains in Okutama will land a better deal that living in Shizuoka, even if commute wise it's probably the same.
This is of course an issue, especially as national policies need to fit both worlds which is a pretty hard (the whole discourse on the spouse wage limit is basically centered on this divide)