So the reason they have not released a +cellular MBP is down to them not wanting to make royalty payments? What do they care? They just roll that payment into the +cellular price bump. It's not like they are dipping into their own billion dollar cash on hand balance.
Do you have a better reason? I think the price difference is probably too high to justify the feature. I don't see any technical reason why they wouldn't do this. But patent royalties and additional overhead related to device certification would definitely add some complexity and cost.
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