A “single channel gateway” is just a “packet forwarder” and nothing more, a real Gateway can handle OTTA, scan all 8 channels, send data to actuators etc. LoRaWAN as an solution for future IoT applications demands real Gateways which complies to the LoRaWAN specs.
I believe that a lot of folks are trying to find a shortcut to more simple and cheaper solutions, and that is good as long as they understand the implications, lack of functionality is just one of them. A full Gateway is the key for good spectrum efficiency and this might be the most important thing for the future.