Long before there was Tesla and SpaceX there was Zip2 and Paypal; both software. Elon is first and foremost a software engineer. Yes, Twitter is social / content. But who better than someone who understands the platform well enough to have 100 Million followers to help take it to the next level?
Success does breed success, but it’s not inevitable. There’s still hard work to be done and his big successes have come from hardware (batteries & rockets). Twitter is software in the social / content realm.
To use your cooking analogy, it’s like saying don’t bet against Gordon Ramsey (an expert in the cooking / media / art / experience realm) if he acquired Virgin Records. I’m sure he has connections and some knowledge that helps, but it’s a new field with new challenges.