The processing power probably isn't the limitation. It's probably hardware, like the number of hardware ports for the cameras are limited. These aren't webcams

The processing power probably isn't the limitation. It's probably hardware, like the number of hardware ports for the cameras are limited. These aren't webcams stuck into a USB hub. If they're physically out of pins, then hardware development will be required, either for some hacky, relatively dangerous (you would be switching out primary cameras), multiplex solution, or the addition of a computer and the support/supply chain nightmare that entails.