A(n Obvious) Motivation for Self-Hosting

Midway upon the journey of our life, I purchased a physical item with an external software dependency, as I did not understand the future consequences of my actions. Petfon (a completely dead company) made a pet tracking system without a subscription, and it was entirely functional. Then, the vendor stopped supporting their Android application; no problem, install using an APK, the hardware functions just fine. Then, the vendor removed their application authentication servers, and the hardware is unreachable and entirely unusable, while remaining physically intact and theoretically perfect. There's no engineering reason why the device needed any external dependency; that server dependency was perhaps added to gather sales information, and never removed. I realized my mistake, it's electronic trash, and I'm moving on. I returned home, and appreciate self-hosting more.