Pathfinder's entire market was "people who didn't like 4E and wanted to keep playing [/selling OGL supplements for] for 3.5," and on that basis they were one of

Pathfinder's entire market was "people who didn't like 4E and wanted to keep playing [/selling OGL supplements for] for 3.5," and on that basis they were one of the only games to come close to matching D&D's success. (They may actually have outside D&D for a few years; it's hard to be sure because WotC doesn't release those numbers.) It was only 4E's divisiveness that let them find a niche, and they started slipping as soon as WotC released a new edition that fixed most of the things that pissed people off about 4E.