To answer the last question, of course it would, especially the pencil support iMO, that why Apple won't do it...It wouldn’t necessarily be a iPad Pro enthusiast type of device… it would be those who want to consolidate and have the best of both worlds. And of course, Mac Mini will be in the discussion… given I’ll be able to plug my iPad/Mac into a monitor and get desktop experience.
You bring up iPod to the iPhone.. and look where that went?
Again, I’m not denying the product is a cool idea. But there’s no doubt that it will take some of the Mac sales… let me propose a question to you.
Imagine bringing iPad-specific features to the Mac (touch support, Apple Pencil and cellular support)… you think that would take some sales away from the iPad?
But was the iPod death a bad thing in the great scheme of things. Not really. Apple is clearly making much more with iPhone. So some forms of cannibalization can make financial sense.
If this device had to replace the entry level Mac Mini, so be it, it would cost $300 more. This would definitely not replace a much lighter MacBook air or a much more powerful MacBook pro 14. It might take some Mac sales but it could still make financial sense given the price, especially if paired with large iPads only, incetivizing their sales.
I don't think the Mac Mini is a consideration for on the go users at this point. You need a powerbank with AC support, use of iPad as a monitor is possible but not seamless and you still need keyboard, trackpad/mouse and stand, not a good solution for on the go at all...