My Tales of the Valiant books work without software or website support. 100% of the content I can own, either in physical books or PDFs. While some adventures may be available only in PDF, all the rules are in physical, printed books that will last for a few hundred years.
These books can be resold, passed down, traded, and enjoyed long after the supporting websites (hopefully never) go away. The core rules are in the Black Flag SRD. While not all the online rules are as complete as Pathfinder and Pathfinder 2, they are still far better than a digital-first D&D 5.5E, with its Drops and digital, subscriber-only content that will vaporize when D&D Beyond or 5.5E support finally goes away.
Tales of the Valiant is an evolution of 5E, and a superior game to D&D 5.5E. It maintains full compatibility with my 10 years' worth of 5E books.
This is the game I chose for 5E.
