" If the consumer realises that all a Mac is, is a computer the same as a Sony or Lenovo, they won't pay the premium."
Which has basically never been the case in the history ~40 year history of Apple.
Going with Intel enables Apple to retain Intel's very generous volume/courtesy discounts on the silicon while at the same time leveraging Intel's large driver and compiler teams.
This in turn allows Apple to focus on innovating in other areas; OS/Middleware/Applications while at the same time improving margins and/or enabling Apple to price their products more competitively.
There's a tradeoff; Apple has to pay ARM for the architectural license and possibly per-chip royalties depending on the licensing agreement.
Apple's competition also pays licensing fees (Qualcomm, Samsung,
Aren't 75% of Apple revenue from iPhone/iPad?
Isn't Samsung the biggest competior of Apple in smartphone and tablet?
Isn't Samsung manufacturing and helping design SOCs for Apple?
Who would going to manufacture this ARM processor for iMac? Most likely Samsung.
Then, what would do Apple good?
In no particular order:
A quick search on LinkedIn for "Binary Translation" (BT) shows something of a mass exodus of such specialists from Nvidia within the last two years. BT was (is?) the essential enabler for "Project Denver"
Apple are looking at how they can continue to differentiate their product to keep a wack of profit. If the consumer realises that all a Mac is, is a computer the same as a Sony or Lenovo, they won't pay the premium. The differentiatr is needed to continue to deliver $8bn per quarter that feeds its stock price.......