The problem is that it is very difficult for even a medium-sized business to make the economics work for a hardware business based on Free Software. As soon as someone releases a device that even remotely gets traction, just watch: there will seemingly overnight be a dozen knock-offs available both undercutting on price and adding features. Great as a consumer, lousy as a (medium/large) business.

As a result, no one with the resources to readily pull it off wants to do so. Eventually it will happen. Hopefully it will be Purism and/or Pine64 because I'm really fed up with the proprietary offerings.