This is exactly how it is. Tony Stark and Bruce Wayne are incredibly similar (including being wheelchair-bound for a short time). They both even have lots of gadgets they use (once is just a suit of armor, while the other's a belt). There's also Jean Paul Valley who built his own Batman Armor. The only real difference is that Tony Stark is no detective (then again, neither was Jean-Paul Valley).

I don't know where anyone got the idea that Iron Man is anything like Green Lantern. Unless anyone can remember a time when Tony Stark was an experimental pilot or an intergalactic using an energy-manipulating device. Or a time when Hal Jordan became a genius billionaire and built a super-sophisticated battlesuit for himself.

The closest Marvel equivalent to Green Lantern is Quasar.