The STEM extension is a recent (2008) development, probably motivated by the fact that H1-Bs are now a lottery so students need multiple shots to have a chance

The STEM extension is a recent (2008) development, probably motivated by the fact that H1-Bs are now a lottery so students need multiple shots to have a chance at winning. Back when Musk would've applied, that wasn't a problem, he would've gotten an H1-B pretty easily. While you can go straight from OPT to green card, getting an H1-B first is much better since it's dual intent, so you're not prevented from traveling during the green card application (which you would be on OPT).