OP, you are conflating two different issues.
Compression is about density, not matchmaker type. It’s about “how many vehicles are in a bracket?” and not “why are these specific vehicles in that bracket?”
Just as a hypothetical example, it would be possible to have a historical matchmaker that suffers from horrible compression: divide all vehicles in the game into two brackets, WW2 and Postwar, with no further bracketing. There, done. Now, Pz III Es and IS-3s are in the same bracket.
This is obviously an “absurd” example, but it serves to illustrate the point: you’re talking about two separate things, compression, and matchmaker type.
So, let’s deal with them separately.
Is there a huge issue of BR compression in War Thunder? Yes, a thousand times yes. No argument there, I completely agree. Nothing more to add.
Independently of decompression, would we be better off if we had a historical matchmaker? I don’t think so. Here is why:
There are a few, clear and very compelling arguments in favour of performance-based matchmakers. First of all, it means that every vehicle ideally (this doesn’t always happen in practice, but in general terms) has a chance to be competitive. Therefore, every vehicle is worth playing more or less equally.
After all, if players aren’t going to play the vehicle, why have it in the game at all? It’s a waste of manpower, working hours, and graphical/sound assets. Investing these resources is only justified if people actually play the vehicle.
Another obvious pro is that it’s easy. You just need to create the vehicle, and done. Drop it in game, see how it does, determine its BR. Instead, if you needed a historical context to justify the presence of every new vehicle you introduce, you would need a lot more work, pace of updates would be slower, and the number of vehicles in game would be much lower.
A game with a limited amount of vehicles can have historical matchmaking far more easily, because the number of variables is smaller. A game that plans on having tons and tons of vehicles can benefit from the relative simplicity of a performance-based matchmaker.
I think it’s obvious which option would be more attractive, if you were thinking about it from a pure business POV.
To make things even more complicated, some of the counters you would need to make historical matchmaking viable, simply do not exist in this game. Like when you say:
This sounds nice on paper, but the problem is that the reality of historical armoured warfare was a lot more complicated than that.
For example, during Barbarossa, Germans in Pz 35 ts still managed to defeat Soviet heavy units with KV-1s. Have you ever asked yourself how that sort of thing was possible? It was because German doctrine allowed their tanks to work in close cooperation with infantry and towed anti-tank guns. We can’t recreate this aspect in WT without overhauling the game mechanics.
There is more than just doctrine, too. You would need to simulate logistics as well. German tanks would have perpetual fuel shortages, limiting how much they can move on the battlefield, or perhaps limited availability of ammunition and (for later in the war) even camouflage schemes.
Artillery would need to actually be the tank-killer it is IRL. Technical faults and maintenance issues for King Tigers would certainly allow a pack of Sherman 75mm and M18 players to win. Making this be competitive and enjoyable for both sides sounds like a nightmare, though. Especially if you then have to do the same, for hundreds of possible vehicle combinations in the game.
If you don’t include these limitations, and go just by numbers, you end up in a situation like the last World War season, everyone wanted to play the Germans in Operation Nordwind. I had so much fun driving around in a Jagdtiger that could not be frontally penetrated by any opponent I could possibly meet, but for that exact same reason, queue times were atrocious, and you ended up often in the paradoxical situation of having ten German players vs four American players just so a match could actually start. Which… yeah.
A game like IL-2 Tank Crew can get away with this, because they have a very limited number of available AFVs confined to one specific historical scenario. It’s impossible to reconcile it with the vast array of vehicles in WT.
One more issue with historical matchmaking is that WT is an incredibly arcadey game. It simply does not have (or wish to have) the simulator aspects that would make a historical matchmaker more interesting, where the sheer granularity of the experience and immersion can overcome the balance problems that the game might have, and make you have fun anyway.
WT clearly wants to be fast-paced, competitive, accessible, and huge. None of these things go well with historical mil sim, I’m afraid.
On a final note, I would recommend looking up custom servers that do historical reenactment battles. There are several which are excellent. I’m interested in that sort of thing too, a more roleplay experience, I just know this isn’t the game that can offer it in its normal modes. But in custom battles with other players, yes, totally.