Steel Division didn't show in the top 200 also owned games for Wargame: Red Dragon owners which would put it at less than 15% of the ~600k WG: RD owners. Going by the SD numbers that own WG: RD it seems like around 50k people own both games.
I'm rather curious as to why there's such a difference... I suspect based on the games WG: RD players mostly own that the WW2 setting wasn't as appealing as the more modern cold war era. Also, Paradox being the publisher seems to have exposed SD mostly to their playerbase. I don't remember seeing SD advertised anywhere other than the marketing emails and posts from Paradox official accounts.
Since I started the trend of using SteamSpy's "game owned" feature to debunk a lot of the "SD is an inferior WG" nonsense, I felt it best to do a bit more analysis based on WG's "games owned" numbers.
The key thing to realize here is that besides Wargame: EE/ALB being the top 2 "other games owned", the rest of the list is actually pretty mundane and typical for your average gamer with a slight strategy bent. Your "average" gamer is mostly going to be playing Civ 5 and Total War for their strategy games; and have a collection of non-strategy games like CS: Go and Left4Dead.
Which means that the EE/ALB ownership are outliers; and given they all belong in the same game series it leads to an extremely simple explanation: A core minority of Red Dragon owners are long-time Wargame players who have been playing since either EE or ALB. This "veteran" base is what's skewing the numbers for what should be "Just another strategy game in a regular strategy gamer's collection".
So the picture that emerges is this: Wargame's audience consists of two main groups. The first, larger group are regular strategy gamers who played RD only briefly. A second, minority group play Wargame primarily and have been doing so since EE/ALB.
Which actually cuts to the heart of the problem and de-mystifies all of SD "hate" from WG players. WG players don't want to migrate to SD simply because they don't want to learn a new game. They've been playing WG for too long to want to migrate.
And note this is a recurring issue with multiplayer RTSs. There is a reason why the best-selling RTS on Steam is
Age of Empires 2 HD, and why we are getting Starcraft remastered. Learning to play an RTS and getting good at it is
hard. Most players who buy an RTS never get to this level and drop it after a few weeks, going back to Civ 5 or CS: Go or Total War. The ones who do learn tend to become very insular and "toxic" because they get really attached to the game due to all the effort they've put into it.
Sadly, the harsh conclusion that can be derived from all this data is thus really simple: New RTSs are simply doomed. It's not about the setting or mechanics or balance. There are simply not enough new game players who want to invest 50+ hours just to become competent in a game and there are too many "veterans" who will end up stomping them anyway before they get there. That's why the RTSs that are prospering today are either ones that don't rely on the multiplayer aspect (e.g. Total War, EUIV engine games), or old classics with huge pre-existing veteran player bases. That Dawn of War 3 - which had a much larger budget and made a conscious attempt to "widen" the base by being more MOBA-ish - got stuck at just 250,000 copies sold is a stark demonstration of the dire position of the genre as a whole.
Edit: Also, the above should really demonstrate why pining for WG4 really isn't going to change anything. Sure you
might get some older WG players to migrate, but it's just as likely many will cite a couple of changes they don't like for the sake of not having to move and spend more money. Meanwhile the real source of new players - which is the wider game market - will continue to see it as a game where they will get stomped and don't see themselves wanting to invest 50+ hours to get good. It's a genre problem, not a problem with any specific game.