Why is full app control over equipment I own behind a paywall?

It just baffles me that I pay for equipment for self-monitoring, and I don't get access to full control over that equipment (arming scheduling etc.) without paying a subscription fee. And I know that pretty much all these home security companies are the same way. I am coming from ADT which is even more of an issue because the equipment was very expensive and is basically useless unless I am paying $70 a month. So in comparison $10 a month to get cloud video storage and full control access is much better... but even still, why do I have to pay at all to fully control the smart equipment I purchased? I guess I naively expected that when I purchase something, I own it entirely and can do anything I want with it. Buy SMART technology, but can't use most of it unless I pay monthly.

Is it because SS needs to pay developers to maintain the app and up-keep it? Might make sense, but none of these companies ever seem to state why. If it is that simple, just be transparent about that. But I mean, does it really require that much from me? No, I doubt it.

SimpliSafe could be a cut above the rest of systems out there if you allow us full control without a subscription. But of course, they would never do that because all their competitors do it.