Brass splits because it's too hard, not from pressure. All normal pressure loads will expand the case to fit the chamber and that's as far as it can go.
The factories are somewhat at the mercy of their sheet brass suppliers, if some lots are too hard it had to be made that way in the original alloy OR received an improper heat treatment at the factory. Either will do it, together they will make some hard cases that split early.
A second problem is that some sizer dies squeeze the necks down far more than neccessary and then the expander stretches it back to normal. This isn't helped by neck sizing unless the neck die has a larger neck diameter. An exception to that rule is the Lee Collet Neck Sizer; it only reduces the neck to the required diameter and not a thousants more.
Third element in short neck life is the chamber it's fired in. If you have a largish chamber, a smallish sizer and hard brass the necks will split in a hurry. Otherwise, it can last a long time even without annealing.
With annealing, case life is almost indefinate. I have some 22-250 brass that's always been loaded to the gills and it's on something like it's 15th trip through my chamber so I'll anneal it soon.