I don't think this is true for all Apple products though, or at least that was not the case in the past. To my knowledge, setting up a free OS on a second-hand Macbook has never been a problem.

However, you are correct Apple is trying to impose new axioms with the iPhones: unique app market (taking controversial posture, such as forbidding alternative browser engines), iCloud lock, non-interoperable hardware (eg. power socket)...