I wonder if there is business in buying those cameras in bulk, flash them with thingio and resell them as "open" camera. Not sure if it's even legal. I guess flashing the camera probably void the warranty and the margin would be razor thin anyway.
There are people using Thingino to provide security camera services. Just selling the cam pre-flashed probably isn't a great plan as I go out of my way to make it as easy as possible for people to flash our firmware themselves!
I have the impression that most security cameras on Amazon are subsidized with their subscription services.
Also, because many of these brands are no-name, you get the inverse volume discounts — you can get 1 camera for less per-unit cost compared to buying 2 or more.
Starting a business may make more sense if you're willing to go directly to the manufacturer, and have the manufacturer flash the firmware directly at the factory. Even then, why would people buy from you at $30 when they can buy an encumbered version for $15 and follow a few instructions?