There are downsides of Aldi though. The first is they don't carry much extra stock and get a delivery every day. So at the end of a busy day in a busier location, they can end up out of several things. The second is their selection is such that if someone wants to just shop at one store only for everything (the most expensive way to shop) Aldi really can't do that. Also some of their great items are seasonal. Their awesome spiral double glazed hams are Thanksgiving, Christmas, and Easter only. And when they're gone, they are gone.
Isn't that how it is at pretty much everywhere?
I mean I don't exclusively shop at Walmart nor Costco nor any other traditional grocery store in my life. I used to do a lot of shopping at Hy-Vee but geez they are expensive now but in any case I still went to Walmart for things even when I did.
Costco has a lot of seasonal items and they frequently shift year to year one year offering a product then the next not. I used to get this really good oatmeal from Costco that was much healthier and tasted better than Quaker Oats but they only carried it for 2 years and haven't since.
For me traditional grocery stores have never given me the full experience I want but neither have places like Walmart or Target. I usually treated Aldi as the supplement place and I think a lot of people do that anyhow. I think if they were intending to be the "be it all" place they would have stores around the nation that are like big box places but on average the square footage of Aldi's tend to be fairly small in comparison. I'm sure that helps keep their pricing down too of their items.
It's been a long time so I wonder if it still holds true but I remember reading that they did an informal study and found that 1) Costco members tend to skew high on income 2) They also shop at Aldi as well