There's a huge difference in peak players versus player average patterns between the game's early life, indicating player retention was rather low. Nowadays there's a much smaller difference between peak and average, indicating higher player retention. The exact stats and reasons are unknown of course, but if I had to guess it's partly because in general people find the multiplayer much more enjoyable now.
I agree with the retention being much higher than at launch. I remember an article in bug.hr many years ago when it launched (gaming/tech magazine). Basically they gave it a 90% rating with the biggest downfall being something in the lines of < horrible optimization, horrible performance, crashes >. They did praise the gameplay/systems in place and the overall feel of the game, thus the high score. Quality of life changes have improved the game.
Regarding the influx. One may never know unless some random hackerman hacks into the space-time and extracts the sql table regarding the nationality of players.
About the "was not designed to be played as a team game RTS". I am pretty pretty sure COH2 was designed around teamgames and not 1v1s. You could say that because only one faction existed on each side that it was for 1v1s... however, the abundance of commanders and the fact that the DLCs were a given (unless the game was a big flop), says otherwise. I am pretty pretty sure, 90% or so that Relic released 2 factions at launch on purpose and had plans to milk more money from DLCs focused around other factions. Why give out 3 or more factions when you can repackage them and sell at a later date, thus higher profits. USF, Brits being 2 factions that cater to a specific audience (Americans and Brits) of casual players. OKW was marketed as "elite super units but expensive". Who doesn't like the sound of that? I too wouldn't launch all the factions at once, that was clever marketing. WFA was released about 1y after the original game. You take into consideration that the first 6 months are about polishing the game once it hits many more systems (more known bugs), you can easily see how the next 6 months are about preparing to release the other factions. British were the icing on the cake probably and were only conceptually realized at base game launch.
I just don't see how this game can be anything but 2v2+. 1v1 competitive? Sure. It takes skill and doesn't favour control groups 1-9 but it's still mostly a competitive mode. You win or you lose. You and you alone. Nobody to blame.
Games function as a source of entertainment and if some people decided to not pursue other more valuable skills at producing new goods, can extract money from it (entertainment is the biggest business)... good for them. Doesn't mean it's not a team game oriented RTS.
1v1 is mostly for diehard fans that lurk around this forum and post either complete and utter BS or constructive well-made arguments, nothing in between like the steam forum which has everything (My God.... everything).
Does Relic need to stop listening to the community? No. Community plays the game.
Relic needs to take into consideration some arguments (if they even read them here) and decide if that suits their vision of the game.
Axis biased people will always ask for pak howi nerf or jackson nerf or whatever.
Ally biased people will ask for Panther, stuka, nerferwerfer and heavy tank nerfs. A normal circle of life on the forums. Everyone knows who is ally biased and who is axis biased. Those people should not be excluded, of course, since they are part of the community but should be taken with a bigger grain of salt. There were plenty of wonderful ideas being written here that could contribute to a more fun game (that's what we all want), not a more predictable game (that's what pro players want). So again, no. The community needs to be heard.