Amazing isn't it? RV'ers still use these places and object strongly when someone points out these kind of differences in price. The Pilot/Flying J business model just does not include RVs and their prices show it. The truckers are not paying these prices, they're all on contract for much lower. Add that to the fact that FJ comes out with a new "loyalty card" or something equally stupid every year or so that either doesn't work at all their stations or has so many strings attached you need your own accountant and lawyer to keep it straight.
Since the advent of Gas Buddy and Google Earth, there's no need to put up with these rip-off artists any longer.