What if I told you patent and copyright law were too similar? Would that make my metaphor make sense?
No, and you’d be wrong. A patent applies broadly to any and all inventions using a similar mechanism, copyright applies to specific instances.
e.g., if a patent on a “fictional hero with extraordinary powers” was allowed to exist, there would not be DC vs Marvel discussions (or if there were, one company would be shelling out money to the other for using their patented comic book formula). Meanwhile, we can have Captain Marvel and Superman (and numerous other permutations of the formula) under copyright law. We can also create software which functions very similarly to another (Lemmy and Reddit) but are implemented via independent means; meanwhile patent law would almost certainly forbid this as it would be based on the underlying central ideas (e.g., communities holding posts which can be commented on and up voted/down voted – each of these things could compose patents or the whole could compose a patent if trying to use one system in place of another).
People often communicate with what is known as figurative language
The criticism on fair use being enforced in the court is fair, but steps into a more general problem of frivolous lawsuits and suppression of competition via the court system; i.e., it’s a not a problem unique to copyright law.