Comic books (at least "mainstream superhero comics") are a bad example for anything, because they run on almost 100% "rule of kewl". They throw any notion of coherence and consistency out the window, and just go with whatever the creative team of the moment thinks is the very most awesome.
That said, Stark isn't the only one who can get his tech working -- his history is now rife with examples of someone stealing his tech and making their own power armor suits.