Coincidence, I think not! Norman dies in TASM2 from his mystery illness. Said mystery illness can be cured by Peter's blood. Harry and Electro fail to obtain this and he passes. Harry is sent to Ravencroft at the film's end. After credits scene involves The Man In Shadows from the first film walking up to Norman's cryogenically frozen head in a chamber and saying, "Wake up old friend.", it seem like Electro was the secondary antagonist, and that Harry is the main antagonist, remember how the Duke of Weselton was a cover up for Prince Hans in Frozen, and how Shockwave was a cover up for Sentinel Prime in Transformers: Dark of the Moon, this could be just like that, it's like rumors are true, that Electro was promoted as the main antagonist, until Harry emerged as the real mastermind.