Aldi is a European family owned chain, same family that owns Trader Joe’s. Aldi’s is their dollar store brand, Trader Joe’s is their “fancy” brand for rich demographic areas.
If your town has a “poor” demographic, like say, it’s part of a big metro area, but it’s the bedroom community with no expensive stores or fancy restaurants, you get an Aldi’s there.
As far as i know it’s just that Trader Joe’s is owned by Aldi Nord, while Aldi US is owned by Aldi Süd. Aldi Nord and Aldi Nord are two separate chains.
Ours is far from a “poor” demographic.
Not only does Aldi have a lot of good products and low prices, Trader Joe has the same. Neither is high priced.