Was saying this because here in France we have a store brand selling in their own bottles, what is in fact Mobil 1 Syn, for a little more than half the price of the same oil in a Mobil 1 bottle. 28€ for 5 liters. Gives ~ one quart for 6,55$.
Here on Amazon we can have 5lt of Mobil 1 Syc SF 0W40 for 52,50€ which is around 61,50$ ~ 12,3$/qt
Have done 165'000 miles with it in a new car with no need to add some between two oil changes, so it's 7'500 miles. The oil always stayed at top level of the dipstick. After 155'000 miles I had to begin to add some.
We know those big stores are not oil makers, they just buy huge amounts and they have substantial discounts.