What's the difference in brand name oil?

I think you answered your own question. I’ve only heard that the difference is in name only.

Oil is just oil, but as I imagine with any product, the plant’s quality standards could different, which could lead to cleaner/dirtier products.

Another aspect would be the moral standards of each brand. Some may have terrible labor or envioronmental practices which could also be reflected in their prices.

These are just a few theories that factor into any company offering a product. I feel its important as a consumer to try and look at the larger picture.

There are many factors that go into different brands of oil. Quality, viscosity, cleanliness, performance. Its a substantial difference when compared to gas which the same truck fills up a different gas station with gas from the one pipeline.