It is indeed. You are arguing that the secret sauce is in the baseband, and yes you can't patent it if the competitive advantage is that it's hard to make so long as it is secret. It's novel, you don't need to patent it to make money as copyright takes care of that... And so to complete the circle patents aren't necessary, and don't benefit society in the scenario you present!

edit: you might bring up clean room engineering that AMD did in the 80s. Intel weren't effected, and are bigger than ever. And the pace of innovation is massive.