Apple still holds the license to the arm arches/designs they've used. There's enough customization applied that I'd guess Apple could function absent ARM, even if it's not the ideal scenario for them.
Plus Britain and Japan are both somewhere between close allies and client states. Nobody cares if we license from them.
Apple is also not a regular ARM licensee. They have a special deal because they were a very early investor when they wanted a chip to power the Newton back in the day.
No they don’t. I mean, that is why they have that license (though PA Semi, the company they absorbed that develops their cores, also brought one along with them); but it’s not a special or unique license. Nvidia, Qualcomm, AMD, etc all have the same license.
Apple is near unique only in that they’ve pretty much never used reference implementations (since the PA Semi acquisition, at least) from ARM and stick to their pure bespoke microarchitectures. But they’re not the only company that could.