That's what ought to be correct, but the recent decision against Facebook on VR cut directly against this view - as I understand it unavoidable mathematical and logical similarities were treated as if patented procedures. Similarity was the only thing considered. Which might force companies to the immense expense of "clean-rooming" almost everything they create to avoid problems. And that might not be a guarantee; patent law is very badly messed up by now, and Congress has refused to get involved in many issues, such as patent misuse (since the current confusion favors large companies/political campaign contributors who can best afford large legal teams and long trials.)