[jerryr]

Yeah, I can see how the cost argument is borderline--it really depends upon what you value & connectivity is pretty important nowadays. But, unless the primary application is specifically "connected robots", I do think it makes sense to omit it for the first rev and get a cheaper product out faster. Don't forget that the $10 is the cost of the part itself.* You still need some support circuitry, hardware development time, software development time, testing time, etc. And then there's markup. Assuming absolute minimal costs for all of those--and direct sales with an aggressively minimal margin, I'd still expect a $10 part cost to translate to at least a $20 product cost.

* Admittedly, that $10 is budgetary pricing and would probably come down with negotiation (and there might be cheaper low-volume options--that's just one I knew of offhand). But that's likely still the order of magnitude for the quantities of the Rex.