This is kinda talking out of both sides of the mouth - “brass doesn’t really matter, but don’t neglect how much brass matters.”
Case capacity and neck tension (uniform thickness and ductility) are critical to ammo performance. Case head malleability is critical to brass life. Some manufacturers do these things better than others - or rather, some manufacturers work slower and harder to achieve higher levels of performance, which in turn is reflected in the price of the end product.
If a reloader puts zero-value on their time, and fails also to consider opportunity costs of time and investments squandered by waste from capacity sorting (waste AND wasted time for weight sorting), equipment for pocket and flash hole uniforming, flash hole deburring, neck turning, etc, then the books are cooked and the comparison of quality brass to big-brand brass becomes inappropriately clouded.
It is true to say most reloaders are not chasing the level of precision required to notice these differences, and true to say small groups can be fired from any brand of brass - but it is also true to say the overwhelming majority of reloaders who spend time and money to weight sort, capacity sort, neck turn or ream, etc really are NOT getting good value, compared to simply buying better brass, or simply realizing they aren’t shooting small enough for any of what they are doing to matter. Same dudes out there doing load development based on 100 yard 3-5 shot group size… just wasting time, money, and energy.
