This isn't very true. Modern copyright, with its many problems, is saner than that and has a more literal view of derivation. There needs to be actual copying involved, not just influence. Likewise with patents claims needs to be unique but also specific. Overly broad and obvious claims are regularly dismissed (if not by the examiner, then in the course of a suite). The problems mostly stem with the litigious ways IP is abused (which of course reflects on the value of the whole system) in that claims of derivation can be made with limited evidence and the recourse will be costly to rebuke.
