As I've said previously ... what we need to do is find another system that has a population similar to that of Shinrarta Dehzra and see if the Earth-like world in that system has night time lights.
While 85 million might seem like a large enough population to put off some visible light pollution that still doesn't answer the question of just how many of that 85 million are actually residents down on the surface. What is the typical operating population of a Coriolis station? And how much of that population is spread out at the other non-Founders World settlements located in the system? That 85 million includes Jameson Memorial, Gallun's Inheritance, Jameson Base, Neumann Camp, and Puleston Arsenal. If we can find some systems where the only human population is located in a Coriolis then we can get a good idea just how many people are potentially living in Jameson Memorial.
Instinct suggests that the majority of the 85 million inhabitants would be down on the surface of The Founders World but instinct in this case could be very wrong. If the surface population is limited to Elites who would actually live long enough to want to retire planetside then actual planetary population might be very small indeed. The majority of the 85 million might not be down on the surface of the Earth-like world at all.
All I'm suggesting is that there are a few items that we need to do some research into before we start pointing to the missing city lights as a breakthrough in the search for Raxxla. I'm just as intrigued by their absence as anyone and one of the best parts of this theory is that there are a few things we can do to try and prove/disprove it.
Good idea, it's testable
https://eddb.io/system/4959 has an Ocellus (iirc 2nd largest type) and literally no-other settlements and a pop of 616k. Orbis is bigger, so until we can find a similar system with just one it'll be hard to tell, but assume 1-2million.
There's no way that more than 1mill people live in the other bases in-system combined, I'd be stunned if the number was larger than a few thousand at the other bases. Even being very conservative it still leaves around 80mill+ "living" on Founder's World.
Just doing a quick check through EDSM:
https://eddb.io/system/12173 - ELW system, 53mill pop
https://eddb.io/system/189 - ELW 150mill pop
https://eddb.io/system/4819 - ELW system, 1.7mill pop
https://eddb.io/system/643 - ELW system 1.1mill pop
https://eddb.io/system/15904 - ELW system 3mill pop
These are probably going to give us the best baseline.
The three with low pops will tell us if lights show with small numbers, and the two that are close to Founder's in pop size will show if there are normally lights at that sort of size. They're single-system worlds with (generally) not too many other settlements, similar to Shinra (ish).
They're all within easy range of the Core too, so no need to go far to test it.
When I'm not hunting Thargoids next I'll go see those places and see if there are any lights on the night-side unless anyone else gets there first (pics or it diodn't happen!).