Right, none of this matters for companies just using ARM core IP. The broadest and rarest type of ARM license that is publicly documented is an ARM architectur

Right, none of this matters for companies just using ARM core IP. The broadest and rarest type of ARM license that is publicly documented is an ARM architecture license, which allows the licensee to implement one of the ARM ISAs with their own microarchitecture. Apple and Samsung both have architecture licenses, though IIRC Samsung recently closed down their CPU design team and so is no longer making use of their architecture license. The normal terms of architectural licenses do not permit the licensees to do whatever they want, they are typically bound by the ARM ISA specification. Normal architecture licenses don't allow the licensee to add custom instructions.