Nicky II was a nice guy in person (though I suppose everyone is nice in person) but a rubbish leader.
Weak leaders are expunged from history, as Nicky and the Tsars were by a bunch of upstart lads who got their start robbing banks. Lenin, and by extension Stalin, were powerful leaders, like FDR or Churchill, who rallied entire nations around themselves to heights not seen before (or perhaps since). To some extent so was Hitler, but Hitler's nation was much weaker than Stalin's, so Hitler was predestined to lose by economic factors, even if his own incompetence and delusions didn't do him in before that.
The only issue at the time was how off everyone was in their estimates of how big Germany was. It took a few years of post-mortem study to tease out the true size of the German economy, helped mostly in part by Germany's lack of information control/destruction of records, which I suppose was a symptom of their own internal delusions perhaps. It's much harder to do the same for something like the USSR, or perhaps the post-mortem of the Western world, where so much records are stored on ephemeral methods (voltage differences in capacitors or magnetic polarities) or where definitions used for data collection are so wildly different as to be utterly alien.
There was no basis to say that Stalinist Russia is like Tsarist Russia except that you're saying you have no knowledge of the former to compare to. Analogies are never really accurate since they never capture nuance, and they should probably be discarded wholesale if you rely on them for most problems. You would think that Germany would have reasonably trained officers in foreign economic intelligence to understand this, but...
Perhaps Germany truly had no good intelligence services whatsoever and was completely incapable of comprehending the magnitude of difference between the two, or perhaps the German leadership apparatus had deluded itself that they were equivalent by huffing its own fumes, but the end result would be the same.
Either the German intelligence officers' reports about "big Soviet tank factories" were ignored because they didn't toe the party line or the officers had been replaced by men who said what the party diehards wanted to hear rather than what was true.
