Your answer is dismissive and misses the point because you nitpicked on one particular word I used that doesn't fulfill one particular and currently irrelevant scenario: Windows in Bootcamp. What about every other scenario?
Saying that "Apple will never allow you to replace macOS" is just plain wrong when they've been allowing you to do that for the past 14 years.
You might as well argue how Bootcamp doesn't run on iPads.
You'd still have to develop all the device drivers required for this custom SoC. After all, Linux doesn't need a license but without extensive documentation and support from Apple it's like saying you're free to challenge your boss openly, it's pedantically true, but it is impossibly impractical for most.
Unless Apple provides extensible documentation for 3rd party drivers to be developed for their SoCs it's just cheap talk from their side.
This isn't much of a "gotcha" - I do think it's outrageous that Apple gets away with selling these gimped iOS devices that only run Apple-approved software.
Would consumers stand for this with any other devices? A stapler where you had to buy staples from the manufacturer? A car that only drives on manufacturer-approved roads? A dishwasher that will only wash approved plates?
Notably the PC standard meant things were interchangeable, not "interlayerable". You picked a CPU, you picked an OS, you did not have to emulate or virtualize whatever you wanted on top of what was imposed on you. Imagine that 30 years ago someone pitched a PC that only runs a specific OS and the only way to run anything else is on top of that like an app. You'd think "ridiculous".
Today having a device that runs as sealed monolith both HW and SW wise, and all you can do is run stuff on top of that without the ability to replace anything is considered a good sign. Tells you where we're going.