Pathfinder had even less marketing than poe2 and sold more, and it was from an unknown developer in their first game. I have my doubts about marketing being the main problem. Personally, I liked both but prefer pathfinder's combat and companions (not all were good though). Evil playthrough is way more interesting too.
Pathfinder didn't need marketing. It's Pathfinder, a well-known quantity at least for all the millions of people who play Pf TT. Same thing for ANY D&D game. Such games already start out with a pretty large core base of fans who will automatically like and buy the game, and you REALLY need to screw things up to sell poorly (i.e. SCL).