I talked to Japanese colleagues about this a lot. The issue isn't just plain old xenophobia. In a lot of cultures, when someone gets married, there are considerations about marrying 'the right kind' for the family. As silly as that might sound to U.S. 'melting pot' ears, these could be tribal, economic, linguistic, geographic, class, education, age, gender, and yes, race.

In traditional settings, the elders have to bless that marriage, welcome the person, and ideally have the families mesh together and be on the same page.

Inviting foreigners with vastly different backgrounds on almost all those axes, it's a pretty tall order to ask everyone to change those attitudes. And saying one family should close their eyes and do it for the sake of the country while their neighbors hold out for a 'suitable' match is going to be tough. The demographic 'time bomb' has been a known issue since the 80s and people are still resistant to change.

At some point, though, realities catch up.

My bet would be it would take a generational turnover and a few years of popular sitcoms normalizing it.