> where the commodity store brand is significantly worse than alternatives (batteries).
Kirkland batteries actually last longer than Duracell. They're some of the best alkaline batteries you can get, especially considering the price. Sure, lithium batteries will last longer, but the mAh per dollar is lower, so they'll still cost more.
That has not been my experience at all. I think Kirkland batteries have less capacity than the premium brands. Also the point of lithium batteries is that they don't leak, not that they last longer.
It’s probably my own battery hygiene, but I’ve had so many Kirkland batteries leak over the years that I no longer trust them. I still buy batteries at Costco, but haven’t had the same issue with the name brand leaking.