I'm not sure this is necessarily such a bad thing?

The kinds of articles NatGeo writes are so spread across the world and really benefit from a diverse set of authors including local/regional/expert ones.

It seems to me that 100 articles on 100 different topics across the globe might be much better written by 100 different freelance authors rather than the same 19.

Regular news publications generally benefit from staff writers who have many years of experience on a particular beat. But NatGeo feels like it's on the opposite end of the spectrum, where all-freelance makes a lot of sense. It means many more voices rather than fewer.