I mostly agree with you, except that nothing is totally impervious ^^.
Quite true. There is always a caveat, but it really depends on how gritty on the details you want to get.
For example, the Leopard 2 has a weak point in its armor on the left side of the tank, next to the driver. There is a compartment here where extra ammo is stored, and it lacks a blow-out panel. It's very unlikely for a hit from the front to do anything to that compartment, but a lucky hit from the side could kill the crew, easily.
And then there is the turret ring - on both the Abrams and Leopard, a hit on the turret ring will easily penetrate into the rest of the tank, but getting the kind of angle where that happens is very difficult.
Neither of these covers other parts of the tank being hit - Commander TIS, gunner's sight, tracks, radio, etc. Just because a round didn't penetrate, doesn't mean you can't make the tank combat ineffective.
As far as penetration goes, the front armor of the leopard and abrams for all intensive porpoises (I couldn't help myself
) cannot be penetrated at a range of 2km's by anything in the PACT armory, except extremely powerful ATGM's like the AT-11. Though if you want to model it as realistically as possible, after 20 or 30 hits, *something* is going to get lucky and do damage at that range.
Things changed once those PACT tanks got within about 1.5km's. All things considered, it could be very difficult for a dug-in NATO force to actually eliminate enough PACT armour that they don't get within that distance, and once PACT armour *does* the fight is on much more equal ground, as NATO front armor would no longer guarantee protection against PACT cannons. Or in other words, NATO would be killing PACT armour in 1-3 shots, and PACT armour would be doing likewise.
Basically NATO doctrine for the cold war was to retreat during an engagement, grinding down the superior number of PACT armour with fewer but higher quality forces. That's the basic gist of it. The Abrams for example, is a big gas guzzler because it was not expected to operate very far from supplies, the idea was that as PACT pressed the attack, NATO armoured forces would slowly give ground with tank platoons operating using reverse bounding overwatch and pre-placed and prepared hull-down positions.
That's not to say that NATO tanks couldn't press an offensive or anything, only that they knew they were facing a superior number of armoured vehicles and utilized what tactics they could to press their intrinsic advantage as much as possible.