The problem for CoH3 is that players apparently decide that the strengths of the game are not worth it. Yes, CoH2 got similar critiques, some rightfully, some as you say because it is new and not what everyone is used to, but the extend seems to be different. All the critique did not stop players from playing, at least not as quickly as for CoH3. Like it or not, but despite a bad release as well, CoH2 had something going for it that CoH3 can't replicate. It might be presentation, sound, whatever.
Having a smoothly running game is great, but doesn't help if the game itself is boring. There's people loving CoH3 in its current form. The overall majority however doesn't, and that's why we see a huge drop in player numbers and the efflux is still not stopped. CoH3 has lost players compared to last week, probably another 200 on average (just estimating), which comes down to ~10% of the player base.
Relic partially focused on the casual gamers, but those will not rebuild the game. They either had their fun or didn't, but moved on either way. They're not going to buy a game with 40-55% positive reviews on Steam. Relic has to rebuild it from their main, die hard audience. Which is not what they have been aiming for, and worries me if CoH3 will get the support that it needs to make it a good game.
You're just making bold claims here as to why people stop playing CoH3, that the game is not good fundamentally or targeted the wrong audience etc etc.
Nearly every single person I have spoken to and myself included stopped playing CoH3 because the map-pool is horrible and I mean HORRIBLE in 3v3 and esp. the most popular mode 4v4. Imagine you play CoH2 4v4 but
only on Hamburg and Lorch Assault all day every day, even the most diehard CoH fan can endure this only for so long.
It's that and axis queue times that kill the MP experience currently. It sucks but both issues can be fixed with ease down the line