I don't know what the future will bring, but I suspect that the Pathfinder core rules came about specifically (1) to keep the rules in print, as you suggest, and (2) to answer the objections about the existing 3.5 system, specifically those brought up by WotC in the 4e marketting push.
RC
I remember on of the Paizo head honchos (Eric??Lisa??) mentioning point #1 specifically. With WotC moving to 4E, the supply of 3.5 DMGs, PHBs and MMs starts becoming very limited, and it gets hard to bring new players in because it gets very difficult for them to find a copy of the rules. PFRPG allows them to have a set of rules that they (Paizo) can print as required.