Some of Starfield’s planets are meant to be empty by design - but that’s not boring, Bethesda insists
(www.rockpapershotgun.com)
It's an engine limitation. The Engine that Bethesda holds onto with an iron fist is what hampers their games.
However, the opposite side of the coin is, that it makes them super easy to modify, so people can make their own additions. Because Starfield is using the same engine as Skyrim and Fallout 4.