You shouldn't confuse Marxism with democracy. Marxism is Bolshevism. That's the first thing. Secondly, why is there now universal prosperity in America, and there are no more Marxists-Leninists? I imagine, yes, you need to have quite an ego to make everyone dance to your tune. And Lenin had it, due to his subconscious complexes. He would never have carried out a revolution if it hadn't been for the First World War. And not the Second (this applies to socialist-Stalinists). He simply calculated everything well, and again, who suffered from this? The elite of society, scientists, artists, all that group of truly intelligent and conscious people, who, if they were with us now, would have led Russia to true greatness.
Many people suffered, yes, but whether they would have led us to true greatness or "messed everything up" is unknown. History cannot be rewritten, and no matter how many guesses we make, it is impossible to say what Russia would be like now.