Which shows what bungling brain-dead incompetents Soviet ordnance managers were - to have this magnificent weapon completely ready for production and then apparently forget about it for two years or so...
Or maybe, just maybe, there were a lot of engineering problems to work out, and production happened just about as fast it could have.
It is true that there were engineering problem to sort out with the design, but that doesn’t change that the machine tools necessary for it’s manufacture were in place. And some of the engineering issues could have been addressed had interference from the peacetime management not withheld permission to acquire certain parts. So no, it didn’t happen as fast as it could, although the difference is probably relatively minor: six months at most, more likely inside of three. The main thing that increases the quantity really will be the T-34 and other bits of modern equipment going into production at a time when the Soviet Union is mobilized for all out war.
Because Stalin's a treacherous weasel, and they don't think they need the USSR.
I've already pointed to a study which makes it quite clear the British in September-October 1939 were leaving the door open for renewed relations with the USSR and hence indicates they would welcome a Soviet entry into the war. As it was, the British in September and October 1939 tried to assist the Soviets in negotiating a trade deal with Turkey, the foreign office seriously floated the idea of proposing a British-Soviet non-aggression pact, they swallowed the Soviets (bogus) excuses about ethnographic distribution in regards to their annexation of Eastern Poland, and were flat-out in denial about Soviet tensions with Finland right up until the moment war broke out.
The prevailing evidence is very much that without the Finnish War, trading Hitler for Stalin was very much something the 1939 Western Allies were interested in. People arguing otherwise have provided fuck-all to back up their claims.
Hitler's political position was undermined in 1939 by his decision to embark on a war which at that time few Germans were confident about winning. The success in Poland got him some credit, but not a lot. It was the stunning victory over France that made the war popular in Germany. In this context, he would be the man who trusted Stalin and exposed Germany to Bolshevik attack. This would qualify as the "setback" that Halder considered a necessary precondition for a coup against HItler.
The start of the 1939 war did not at all undermine Hitler’s political position. His prestige and credit as the man who had demilitarized the Rhineland, overturned Versailles, forced the Anglo-French to back down. He was able to deflect blame to the Anglo-French and convince the German people that they were the victims of Anglo-French aggression. Halder repeatedly flinched at coup attempts and went to great efforts, so he isn't about to overthrow Hitler in an attempt that, by his own estimation, was unlikely to succeed.
How exactly did defeating France add to German resources? Some captured vehicles, PoWs as slave labor... Yes, there was some industrial loot. But look at all the claims on German resources resulting from the western campaigns. Germany had to garrison occupied France, fight the Battle of Britain, garrison Norway and the Low Countries, defend against British bombing. Plus Germany fought the Balkan campaigns, send the DAK to Africa...
And with all those drains, Germany carried out an offensive against the USSR in 1941 that was enormously deeper that what I suggested here. Remember, this is the army that took three months to defeat Finland against the army that crushed France in six weeks.
I don't think it's overestimating to suggest that in a year of campaigning in this context, the Germans would advance as far as they did in two months in OTL 1941.
It wasn’t just vehicles or PoWs and the fact your claiming that reveals your gross ignorance. The Germans captured the entirety of Western Europe’s resource-industrial vase, with massive infusions of strategic materials seized from stockpiles and spare machine tools to prop up a German economy that otherwise would have collapsed in late-1940, along with additional slack that, when exploited at the expense of the inhabitants, basically fueled the entire Nazis war economy until 1944. The costs in garrisoning the occupied territory with divisions and Rommel’s small hunting expedition in North Africa comparatively were a drop-in-the-bucket compared to the gains and certainly much lower then having to maintain forces against a large active enemy army on Germany's western flank as would be the case IATL.
In particular the entire logistical base for Barbarossa, both in terms of immediate acquisition and the manufacture in '41-'42, was basically enabled by the conquest of Western Europe. It is by the German quartermaster staffs own admission that they would have never been able to supply their forces as far as the D’niepr without it. So yes, it’s a gross overestimation.
Stalin attacking all out? Might be just a little alarming? Romania and Hungary stayed out of the war in OTL 1939-1940 because they had nothing to gain or lose. Romania submitted to Soviet demands in July 1940 because Germany wouldn't back them (the Hitler-Stalin Pact covered Bessarabia). ATL, Germany and the USSR are at war. They can sit on their hands and hope Germany wins, or they can join. If the USSR wins, they are dead meat.
If the USSR wins, the Romanians and Hungarians can still count on the Anglo-French backing them up, so no they aren't dead meat. If they do join and the USSR wins, which is likely, then the Anglo-French are going to leave them to the wolves. So they have everything to lose and little to nothing to gain.
Yeah, that's about right. Soviet losses declined substantially - from megacatastrophic in 1941, to horrendous in 1942, to merely severe in 1943-1945. (E.g. 30,000 KIA at Seelow Heights in April 1945.
(Horrendous in 1942? Consider Operation BUSTARD HUNT, in May 1942, where the Germans cleared out eastern Crimea. The Soviets lost over 170,000 men - the Germans 7,500. Or FREDERICUS (the same month), where the Germans crushed the Izyum salient, inflicting 270,000 casualties for 30,000 of their own. Sure, by this time, the Soviets could survive such blows without great disruption. But to paraphrase Everett Dirksen, "100,000 men here, 200,000 men there, and pretty soon you're talking about real losses.")
And a lot of this had to do with the fact the Germans being able to bound forward hundreds of kilometers in the space of a month resulted in mass devastation of Soviet forces that disrupted and delayed Soviet attempts to improve their forces as well as denied them considerable resources with which to do it. The massive advances of 1941 forced the Soviets to basically jettison their entire military reform program and they were only able to restart it at the start of 1942. IATL, there’s none of that and the Soviets have had a considerably long time to peacefully process the combat experience of both the disaster of the first opening offensive and the subsequent static fighting as well as considerably more resources to do so with. If anything, the Soviets will improve substantially faster then the Germans can handle.