Tony Classic ends up dying, paving the way for Teen Tony to stay in the present and take over his adult life. Yup, Iron Man basically died and was resurrected as a teenager, like some cross between the New Testament and a copy of Tiger Beat. Because this was dumb as hell, the writers eventually brought old Tony back through vague retroactive magic. He still felt bad about all those murders, though.
To show you how little of a crap anyone gave about Iron Man at the time, Marvel didn't re-acquire the character's film rights by writing a check; they simply waited until New Line Cinema let them expire after years of not bothering to make an Iron Man movie. So why start their cinematic universe with him? It had less to do with the merits of the character and more to do with the fact that they gathered groups of children, showed them pictures of superheroes, and asked them which one they would most like to play with as a toy.
This strategy backfired when it turned out that no companies wanted to make or even stock Iron Man toys, because who or what the hell is an Iron Man? See, Marvel held focus groups during which they learned that most people thought Iron Man was a robot, not a functioning alcoholic inside a suit. They even produced a series of short films for the sole purpose of raising "awareness" and illustrating that there was definitely a guy in there ...