That could happen for ordinary people and companies who have to rely on commodity processors or who license ARM cores and add their own peripherals around them

That could happen for ordinary people and companies who have to rely on commodity processors or who license ARM cores and add their own peripherals around them on a custom chip, but Apple designs their own ARM processors. They have an ARM architecture license. They design their own ARM implementations from the ground up. If something can be done to RISC-V designs that would leapfrog ARM and ARM does not want to incorporate whatever breakthrough that is into their own cores for some reason that will mean that the people who rely on commodity ARM chips or on licensed ARM cores will be out of luck. Apple on the other hand would be free to incorporate that into their ARM implementation.