Apples customers
I'm sure Apple knows its customers better than I do, but it will depend on how the market share breaks down between consumer and professional.
I can't see professional users who, in my experience, replace equipment as soon as a new model is available, would be prepared to use a product that was significantly slower. Apple have been there before with PowerPC and it cost them a lot of previously happy customers. And these customers know about the performance of emulation software....
If, on the other hand, Apple plan to release a Chromebook-type device that benefits from the existing iOS infrastructure while providing more CPU/GPU/screen size, I can see that possibly working. Particularly if it becomes a Macbook Air and is replaced every 12 months with a newer, faster CPU and is "fashionable"....