On the Food network they boil potatoes, but they poach carrots. They poach turkey, but they boil eggs. They sauté’ onions, but they fry eggs in the same pan. Likewise, they fry hash browns, but they sauté’ onions in the same pan before adding the potatoes.
I can go on for days.
I think you saute at a lower heat than stir-frying
I guess you replace the oil with the extra stirring to stop it sticking when you stir-fry
It is actually the extreme heat that prevents sticking more than the oil. You can stir fry in a dry wok. The stirring is for even cooking.