I have the same question. I thought it to be more polite to bump this thread than to spam the same question again.

Any answers?

some nations it gets pretty close most majors will get pretty similar counts by the late game. but it wont be perfectly historical. nations that had large division counts but have few factories in game will have a lot less than historical, like china or Bulgaria. still much more realistic than the vanilla game though where every major has 1000+ divisions.

the soviets had something like 300 divisions in total when barbarossa started, but it's more complicated than that. different countries had different division sizes, and even these varied as the war progressed. after massive losses on the eastern front, the average soviet division had only a fraction of the men they were meant to have. for example, in 1944 the average sov division only had 3k men, while the average german division had 17k men. the soviets had nowhere near 700 full strength divisions at the end of the war, and the germans had nowhere near 300 full strength divisions either.

the US, which had full strength divisions for the entire war, only mobilized 91 divisions to conserve production capacity. this is not simulated in the game at all, and late game America will have like 600 divisions with a thousand factories all churning out infinite equipment.

basically this shows how insanely bad HOI4s core game design is. there is no mobilization mechanic, so even countries at peace will have their full army on the map sucking up computer resouces. even vic 2 had conscripts that could only activate during war. same with hoi3. random 3rd world countries in latin america will slowly create more and more divisions out of thin air and somehow maintain them with magic.

in vanilla late game a country like estonia will somehow be able to feed and supply 40 divisions during peace time (if they dont get invaded), because food production is not simulated and factories don't use any manpower. manpower itself grows infinitely and thus the ai will spam infinite divisions while taking tens of millions of casualties. i played as the soviets till the 1960s once, and the allies had suffered like 50 million casualties thanks to failed naval invasions. still the uk and the us had like 1500 divisions in total, slowing the game to a crawl.

basically the whole game is broken, and they would rather release piece meal DLCs selling focus trees rather than re make the game from the ground up in the form of HOI5, which is what they should have done years ago. the only decent dlc they've released is no step back and it's pretty much the only one i've bought. mods can't fix this game and it needs to die.