Apple has never stated that the MacBook is going to go away, replaced by the iPad.

They have said that some people have found iPads to be a suitable replacement for a notebook. And some people use them AND a notebook/desktop.

The fact that they're selling them side-by-side is also irrelevant to the discussion. There are use cases for both, and some prefer one over the other.

Apple will sell what you prefer. Why shouldn't they?

They know full well that it's better to cannibalize your own sales than let someone else do it for you.

I feel like you setup a straw man just so could knock it down.