In USA and many countries patents last up to 20 years. So what is special in PMC's case.

Profile of PMC (As per their website: www.personalizedmedia.com )-

"Personalized Media Communications (PMC) owns a fundamental patent portfolio relating to the control of networked equipment, including online and mobile environments. John Harvey, PMC’s founder, first disclosed the inventions in 1981. All of PMC’s patents claim priority from 1981 or 1987 and have terms lasting until at least 2027 with many lasting until the 2030’s. PMC's portfolio consists of over 100 issued patents."

With reference of Personalized Media Communications, LLC v. Apple, Inc. (E.D. Tex. 2021)