Trader Joe’s is fascinating. Their own products are unique and you develop a craving for them. That creates serious retention. And over time they’ve designed out more and more third party stuff, replacing it with their own (instead of selling both alongside each other). I’ve never read a business case about them but it seems like a killer strategy
Trader Joe's is Aldi's chain, right? Do you have Aldi too in addition?
From my experience the US Aldi (which is part of an Aldi Sud) is a dimlit, bottom of the barrel discounter with a small selection of basics. Where Trader Joe's is a quirky "Hawaiian-themed" specialty grocer with a good selection of the unique-to-US products.