That's usually the point of these alternate universe things, that a lot of things are similar because the characters and situations are similar, just one thing changed, and we're watching the butterfly effect of it.
Did Stark have the Tesseract in the movie? It's been a long time since I've seen it, so I don't remember. Because I think having a source near limitless power the size of a rubix cube would change what you're able to pull off.And an iron man suit in 1942? Come on man…he couldn’t get a car to levitate for 5 secs at the science expo in the movie.