Yeah, but people keep telling me that he's a genius and invented so many things.
He's
invested in a great many things that have become successful. How much he has done him self is debatable for sure. One thing I can say for sure because it's public record, he didn't come up with most of things that made Tesla, Tesla. The original founders did. Musk was the VC, but Musk was a smart VC and wrote the terms so that he could just whisk the company away from the founders if it became successful, and he did, thus getting all the credit because most people had no idea what Tesla was until after it took it over from the founders.
As for PayPal, as someone who grew up in that era, X.com was nothing special, Confinity on the hand could allow someone to setup payments to another person. This was a big deal back then. The reason for them merging made sense, but PayPal is much closer to what Confinity was than what X was. X.com was basically like logging into BoA today, plan, boring bank site (still a fair feat for back then).
For Space X I don't have information to draw on. It could be all him or could be him playing the typical VC role. There just isn't enough information out that (Patents can't tell you because the submitter can put there name on it. Look at what Edison did).
I won't take all the credit away from Musk however. VC vision plays an important role in technology development. However, he definitely gets credit for things that probably shouldn't get credit for.