When the game was first announced, they trumpeted historical authenticity and realism. It is not an 'issue' that a consumer should hold a product to its advertisement.
As am I. My favorite game, currently, is Sins of a Solar Empire. This is not a 'realistic' or 'historically authentic' game. The thing is: it doesn't advertise itself as such, so why would I expect it to be?
These two things are not mutually exclusive.
"Failure" can occur from a great many things. Such as losing money because you failed to provide what you advertised.
Ignoring the 'lol umad' meme, let's go ahead and make this real simple.
Did they advertise historical authenticity? Yes.
Is the game historically authentic in any way, shape, or form? No.
With regards to this nonsense about American 37-mm guns being able to penetrate the front vector of tanks like the Pz.Kpfw V, they can easily change this by switching around some numbers. Fair enough. They might even do that. But there are a great number of OOT units, botched TO&Es, etc. that constitute a total failure to provide what they advertised. No amount of strawmen pulled by you, or anyone else, is going to change this fact.