My pet conspiracy theory about these leaks is that the military uses WarThunder as a training sim, and every now and then someone notices the physics/render is off so they "leak" the specs knowing some gaming nerd is going to fix it for them.
The devs cannot make the game match the reality, because that would be very very unfair for the people who play non-NATO countries. The game needs a semblance of balance.
At least at one point, Russian tanks in the game had just free magic armor to protect the ammo carousel from cooking off from literally any hit. "Spall" and damage fragments would just magically not trigger the ammo cookoff, specifically on some Russian tanks.
It doesn't really change the fact that quite a few militaries license "MCS", the military version of the simulator for training purposes (and it probably funds DCS development as a side project).
You could even see it now in photos with Ukranian pilots, most likely for F-16 cockpit familiarization.
Remember that pilots spend quite a bit of time practicing on printed out posters of cockpits and DCS is quite better than that ;)
For Arma it's VBS, but the games company (Bohemia Interactive) and the simulator company (Bohemia Interactive Simulations) have been seperate for quite some time, so VBS is based on older Arma titles.
IIRC the PLA actually used modded Arma 3 for training.
