Can you described the new tactic developed by the German to re-emplace the Blitzkrieg? Name, if possible. Even in Kursk, the German tried to cut the Red Army from the rears, and to apply the same good tactic. No innovation, no new concept just a bigger scale. In defensive, they used the kessle, in offensive the blitzkrieg (without the means, air superiority).
The only people who defeated the Red Army when this one was ready came from your country, with the use of the line Mennerheim, light infantry, lot of sub-machinegun (Suomi) and skilled people using properly the terrain.
Prove me wrong and provide something else than an opinion, I will be happy to consider your facts and analyses.

If the Blitz was so old and outdated, why did both America and Russia adopt it and use it until the end of the war? America still uses it in a different name.

But ok, we'll just say that the Blitz was worthless after 41. What about the Kampfgruppe? The allies never reached that level of organizational freedom. I would say that strategy - tactic - whatever, was almost as important for the post war world as the Blitz. Ironically, that form of warfare was used by the Israelis to great effect against the Arabs.

Read up on Manstein's use of this form of warfare, its amazing what he was able to do with units from all different commands to form a functional fighting force... or just look at Market Garden.