Yaarel
🇮🇱 🇺🇦 He-Mage
I see it as the responsibility of each setting, to define and exemplify the prominent backgrounds of each culture.This is because Wizards is getting out of Culture, because its too specific for their overly bland, generic, 'multiverse' approach to character creation and settings.
Core rules need to work in multiple settings, thus tend to be broad and suggestive. But specific settings can be highly specific, and local.