The Things Network is a non-commercial initiative and in most places of the world there currently is no TTN gateway coverage whatsoever.
Therefore success of The Things Network greatly depends on enthusiasts. Enthusiasts of who most don’t have the money to buy their own gateway (or are not willing to spend hundreds of dollars to it). Without gateway coverage it is impossible to experiment with nodes which results in much less enthusiasm and less growth of the platform.
A parallel with this is people who are interested in (experimenting with) driving a car and owning their own car. Most of them are interested solely in driving and going to places, but not in having to build their own roads before they can drive the car at all. (Mind you, there is no such thing as 4WD off-the-road TTN nodes that can function without any gateway.)
I understand that from several perspectives single channel ‘gateways’ are not ideal (at all) but I think that single channel gateways will be inevitable. Use of LoRaWAN technology is growing and for non-commercial use many people who don’t have existing gateway coverage will start experimenting with the technology using single channel gateways.
Therefore it would be good to not just condemn single channel gateways, but find a good solution to let them coexist and support them (in some way) and provide good guidance.
[update]
Above post is outdated.
See: Single Channel Packet Forwarders are deprecated and NOT Supported [guidelines]