The age API is not a prerequisite for adding a location API.

You start with the age verification because "think of the children" is an easy sell, then a year from now, there'll suddenly be a massive worry about criminals using their phones for "crime-stuff", so we need to track where these people are - there's then already a system in-place for easily adding such a functionality

A year after that it'll be online fraud that is apparently rampant

My reason for this conclusion is that there's no good reason that age verification should live at the OS layer. It is technically cleaner and simpler to have it as an external service - just look at the amount of issues it's causing for Linux distributions

FB are not dumb - they know this hurts Linux distributions, but they're an ad business and they need PII to sell those ads