C yer point guys , and yes with some premium oils u pay a disproportionate amount of the purchase price 4 the brand name.
However , using the buy cheap and change often routine , u wud have 2 change probably 3 -4 times more frequently with an inferior oil 2 b safe , which wud b virtually the same as using a quality oil 2 start with.
There r many factors 2 oil chemistry which r invisible 2 the customer but affect the life of an engine drastically , 1 of the primary factors is the base oil used by the manufacturer , low price brands use a low grade base because this is the highest cost factor , but cheap base stock will break down surprisingly quickly.
The best synthetic brands r the US makes , they use the best base stock and additive packages , this stuff can be relied upon 2 protect an engine.
However if u have convinced yourselves that low price brands do the job then it's your choice.