I don't know, most of the things I'm reliant on, from my phone, ISP, automobile, etc are built on fragile interdependent supply chains provided by for-profit companies. If you're really worried about this, you should learn survival skills not the academic topics I'm talking about.

So if you're not bothering to learn how to farm, dress some wild game, etc, chances are this argument won't be convincing for "why should I learn calculus"