Do you have some examples? Genuinely curious. To my knowledge, most of the major FAANG apps are single-binary.
Why? I have no idea.
Google Pay is another one. They have a dedicate app in Singapore.
It seems like a lot of them went to single apps when they realized they could download data packs within the app. Stuff like Rick Steves guided tour apps used to be separate per city, but now it's a single app where you download the data for a certain city.
But I think you're right that all the major FAANG apps are single-binary.
Worked on iOS app size at a FAANG for a couple of years -- this is untrue. At the very least there are different binaries for watch vs iPhone architectures.