Factoring these (very diverse) game genres:
Space themed games:
- Galactic Civilizations
- Sins of Solar Empire
- Early release space games like Evochron, Empyrion Galactic, Avorion, Executive Assault, Between the Stars, Asterox Imperium
- Planet Nomads
- SW KOTOR
- Space Engineers
- NMS
- Everspace
- Stellaris (and other non space strategy build games like Civ)
- X3 Reunion/X4 Foundations
- Starpoint Gemeni 3
- Upcoming space themed RPG games like RGO & The Outer Worlds
Non space themed titles like
- TES/Arena/Daggerfall/Morrowind/Oblivion/Skyrim
- Fallout 1 - 4, Fallout NV
- KCD
- Dragon Age
- Fallout 76
- The Sims
- RDR and RDR Online
- GTA VC, GTA III, GTA SA, GTA IV, GTA V & GTAO
- Farming Simulator 19
- SimCity, Cities Skylines
- Subnautica
I'd guess easily ~ 350 to 400 or so consistent friends I communicate with frequently in game and on external 3rd party channels like Discord and email. Randoms increase that number considerably from interaction in game and game forums like this. But from the larger, strategic fan base perspective, that number could easily surpass 1,000 PvE minded players. ED as a space sim just needs to have depth, clear progression for pilot development, and immersion in character lore, NPC development to attract the PvE minded player. FDev made the first steps towards this with the Sept release update that helped n00b Cmndrs. The result was a significant boost of ED's player base on a PC forum like Steam's Top 100 popular games.
Because unlike most PvP gamers, PvE gamers don't rely on other players for their emergent game play content. They're perfectly comfortable creating their own i.e. via main story/quest lines like RPGing a faction like in ED's PP ones. Or doing creative sandbox to develop their character and/or RPGing within the framework of game lore. Or combination of all three. Their primary focus is on the game world environment and how they can interact with it. Either with other players in a collaborative sense or solo. The true number of these PvE gamers is significant higher than is assumed in the industry IMO.