Not anarchy, Nuke. It's the way the patent system and any attendant litigation has always worked since the 1952 Patent Act revised the much earlier Acts in early and mid 1800s. Different patents have different claims directed to different respective inventions to which different/same prior art may or may not be applicable. 35 U.S.C. 102 and 103. Other defenses against patent validity exist, e.g., those set forth in 35 U.S.C.101 and 112.  Court trials or PTO reexaminations(with subsequent appeals to CAFC) determine the patentability/validity results in new cases, along with Court-determined infringement results.