You can also sue anyone using the power amplifier in any product sold in the USA. I don't know why you use ARM as an example. I don't see how ARM would survive

You can also sue anyone using the power amplifier in any product sold in the USA. I don't know why you use ARM as an example. I don't see how ARM would survive in a patent free country. In fact it's probably example 1A of why patents are useful device. Why would Apple pay ARM if they were totally free to use it.