There are many reasons why quitting your day job and growing a presence that will get you sponsorships is worthwhile, and I am a strong advocate for paying open source devs who maintain the packages you use. However, if you're thinking of trying to copy Caleb's success, remember that it'll take 28 years before he'll have earned more than he would have if he'd kept his $90k/year job.
Arguably a talented dev will never earn more than if they'd had a job instead. Open source is a route to working on something you love, but you will be leaving money on the table to do it unless the landscape changes a lot.
There is still a ton of change necessary in the open source model before it becomes a viable 'job' for most people.