I majored in math and have so far a great career in software. I don’t think knowing math separates me out from CS grads generally. However, math majors largely chose to major in Math because we like problem solving. Plenty of CS grads major in CS because they are expected to. Being a passionate problem solver gets you pretty far.

With Garmin, you’re paying a premium because you’re not the product.

https://foundation.mozilla.org/en/privacynotincluded/garmin-forerunner-series/

https://foundation.mozilla.org/en/privacynotincluded/garmin/

A natural monopoly is when an industry is difficult to break into, making competition difficult or impossible. This favors incumbents, in fact, a lot of industries are natural monopolies (pharma, aerospace, chip production).

The difficulty of breaking into an industry may be because:

• new players cannot compete with established scale
• start up costs require a nearly all-or-nothing approach, high risk
• regulations tie the hand of new innovators

Have you thought about ways to monetize your project? That’ll be a great to show off on your resume if you wanted a conventional job. Even implementing AdSense on your site will get some folks interested enough to interview you.