Some of Starfield’s planets are meant to be empty by design - but that’s not boring, Bethesda insists
(www.rockpapershotgun.com)
That did actually get fixed later on (like in 2018) - there's now undiscovered systems that you can stumble across, along with abandoned systems. Can kinda see why it took a while to get added - undiscovered systems are kinda...boring.
The sentinels are there, but that's because they're basically semi-divine beings and seperate from everything