I would too if they offered lower price on items. But they don't so I am not doing their work for them and paying the regular price. Same thing with gas stations. It's a way for owners to earn even more money on top of premium they are already scalping off of us.
Gas stations do not make money on gasoline. They only get a few pennies per gallon. They make their money on the inside sales of pop/beer/twinkies/roller dogs. The oil distributors set the gas prices, not the station, it's real time pricing. The station doesn't even own the gas, until it comes out of the pump. While it is in the tanks in the ground, it is still the distributors. It's one of the few real Just In Time pricings you will see.