Oxidation of oil is a breaking down, or maybe better to say deterioration due to addition of oxygen. This usually comes from heavy use, pulling your camper/boat, and higher than normal oil temperatures, stop and go city traffic, pulling/hauling heavy loads. The higher the oil temperature, the worse the oxidation deterioration. I read an article on Opie Oils that said oxidation doubled with each 10C rise in oil temperature above 70C(158F). One of the products of oxidation is peroxide, which is itself a cause of oxidation. The more an oil oxides, the more, and more quickly it will oxide.. The longer the miles/time between OCI, the greater the potential for oxidation.
Antioxidents/oxidation inhibitors are added to oils to increase its resistance to oxidation which increases its service life. This service life may be much less for my pickup worked hard than for my car driven easier and at highway speeds. Without the inhibitor, the service life of both would be much less.
How these inhibitors work, I don't fully understand. I have read tech articles that say they either neutralize the peroxides or encapsulate the peroxides.
I can understand Mobil adding extra antioxidents and extra anti wear and friction modifiers to the SUV oil. However, at least where I live, the Mobil 1 5w30 and 5w30 SUV are the same price. Why don't they add it to all their oils, at least the 5W/10W oils, if it makes the oil last longer and protect better? I guess I am wondering, What is the down side or the negative? I am inclined to thing that Mobil found a market and made a product that you can test and prove is really meant for that market. If I used brand X and discovered the Mobil 1 Truck and SUV I might be inclined to think , "here is something made special for my new truck(which calls for a 5w30) that is much better than "STANDARD" oil."