Zerg rush has its place, but there are various things that have to also be in place to make it effective
I am speaking of when those things are not in place. Germany messed up bigtime in that campaign, so as much as it was credit to soviets, it was a disaster on Germans side with many mistakes made. Never underestimate an opponent, or a foreign land/weather or a foreign people.
I am speaking of those times when swathes of men run at bullets and get cut down and they just die and achieve nothing. Unless absorbing bullets was the goal, then goal achieved.
You are only talking about the times when it works, which is usually due to the factors you will ignore for the convenience of your argument.
For example in Vietnam the vietnamese fighting the americans had no choice but to charge at the enemy in certain situations, because their enemy had total air superiority and control and superior artillery. So their only chance was to get in close quarters so that the Americans would not drop bombs and shells on their own men (despite that happening on occasions). So they laid ambushes (camping) very effectively, and then moved on before artillery could hit them. Though this was not always the case. They too made mistakes and ran at bullets in the wrong places and times.
Mel Gibsons movie of landing zone style warfare on helicopter was a great example of when zerg rushing fails, based on real events. However the movie doesn’t cover the other battlegroup that got completely wiped out by the vietnamese zerg rush there in a different landing zone. All of the americans were killed there on that zerg rush, because the numbers were just too great. But that is a number superiority effect. Which is not always a guarantee for victory either.
But again, different conditions and factors decide which zerg rush wins, and which zerg rush fails.
And my suggestion makes you think more carefully about when to engage it.
Whereas you seem to think it must always be employed by these other players, when that is not always the case and when it is, you have to be aware of what the situation you are rushing into, because if you just run carelessly and don’t clear, you will be cut down.
For example you run in and a tank has the spot on lock, he is going to murder your entire squad and anyone else in the vicinity. Because you did not consider that problem.
And now, if you keep going in there and getting obliterated by the same tank in the same spot and you keep doing it again and again, you are not going to get a different result until you acknowledge that the tank is a problem that has to be dealt with first before running into that same spot again.