The Human Target
Adventurer
That's an inaccurate statement, IMO -- mainly because maybe 50% of the full body of Pathfinder rules, probably less by now, comes from the d20 SRD. Not only did they do significant changes on the base rules (with community input and playtest) but the Advanced Player's Guide, Ultimate Magic, and Ultimate Combat comprise more rules work than the Pathfinder Core book at this point. I've seen comments occasionally like this, as if the Pathfinder RPG is just some reprint like Mongoose Pocket Player Handbook or something, but it's not true. It's the whole "Ship of Theseus" thing again.
Oh for sure they added plenty of stuff.
But the base game was given to them, and given to the general public.
So to me its easier to give an altered version of that out.