I love this advice, and it took me a while to figure out that for me the intersection is Developer Advocacy. Math, software, public speaking, writing, comedy, business = Dev Advocate at a bitcoin company. I'm not great at any of them individually, but good enough at all of them to make a great Developer Advocate. Took a while to convince someone to take a risk on me (I had a technical Biz Dev/PM background prior to my current job) but finally got a company to interview me the right way...they had me present to 20 bitcoin devs about their API as part of the process, and I happily can say I knocked it out of the park. Barring any sudden discovery of me as a stand-up comedian/writer (unlikely at this point) I'm very very happy to make a long, fruitful career of this role.

Anyway, TL;DR: there are always ways to combine software with other skills. The hard part is finding the role that incorporates all of them (whether you invent it as a founder or join someone else).