This I think is an excellent model and has worked for FOSS communities in the past. One example of a similar strategy is RHEL, where you pay for support rather than software. Of course with hardware it is different, you will pay for the hardware, but the price increase for consumer purchased hardware reflects additional cost of customer support. I think this is a viable and ethical business model.

On another note, I hope to one day see projects like pine64 specifically using RISC V architecture.