I understand adafruit's take at it. But I guess they are simply plain wrong when saying 'incompatible', at least from a pure license perspective for the HW/firmware.

As other pointed out, companies like Google demonstrate, how open source can be used in a rather aggressive commercial strategy. However, I think the good news is that that the open hardware stuff is not rocket science and maintenance hell at this point (without the new Qualcomm bits). I guess it is now for others to step up and make the ecosystem resilient. That is IMHO the power of open source in case it works.