I think that there is just a finite way of making money. Offline commerce also hasn’t changed in a very long time. You basically either sell products or offer services. The rest is just about marketing and finding clients. Online commerce didn’t reinvent the wheel, it just moved all these activities on the Internet. While the marketing side has changed over time, the overall principles were always the same.
People are turning to audio and visuals when it comes to technical subjects. However, you should consider doing an ebook first and turning it into an audiobook through a resource like Audible's ACX platform. You can hire a producer either through a royalty share program, so you don't have to shell out upfront cash, or you can do a pay-per-hour hire as well.
Double check yourself, before you double wreck yourself. Make sure everything you send to a company, whether a résumé, an email or a portfolio, is good to go. Double check your grammar and wording, and for God’s sake use spell check! This is especially important when it comes to the company’s name. Don’t spell their name wrong and be sure to type it how they type it (e.g. Problogger, not Pro Blogger).