people are going to hate me for it but I'll probably enjoy it
So if Tony Stark knows the secret of cold fusion, why doesn't he mass produce suits?
why would he?
he's the only person who gets to use them and he's already got a few of them already (the one used by the mechanism in his tower, the briefcase one from the second movie, and the wristband-lock-on one from avengers for instance)
the whole point of the first movie was that he wanted to stop making weapons for other people because they always ended up in the wrong hands (those terrorist guys who captured him in the beginning had a truckload of stark weaponry)