Aldi Sells 1,500 Things. Walmart Sells 30,000. That Gap Is the Whole Moat.

Walk into a conventional American supermarket and you stand before more than 30,000 distinct items — eleven kinds of ketchup, a wall of cereal, an aisle of olive oil priced by the centimeter. Walk into an Aldi and the whole store holds something like 1,400 to 1,800.⁵ It feels like less. It is, in fact, the entire engine. The thin assortment isn't a sign that Aldi is poorer or simpler than its rivals. It's the lever every one of its cost advantages is pulled by — and the one thing the giants across the parking lot structurally cannot pull.

The official story is that Aldi is cheap because it's frugal — German thrift, no-frills stores, a quarter you put in the cart to borrow it. That's the costume, not the body underneath. Aldi is cheap because it made one radical decision about how many things to sell, and then let that decision cascade into everything else.

One number does all the work

Start with the choice and follow it down. Sell roughly 1,500 items instead of 30,000 and you no longer spread your buying across thousands of suppliers and brands — you funnel the entire spending power of a €112-billion business through a narrow set of products.⁷ That concentration is the source of Aldi's purchasing terms: limited SKU count gathers total demand into a few lines, which is exactly what pries favorable conditions out of suppliers.⁴ A conventional grocer buying one pallet of forty different mustards has no leverage on any of them. Aldi buying a mountain of one mustard has all of it.

The same number that buys cheaper also builds smaller. Fewer items means a smaller store, fewer shelves to face, fewer prices to change, fewer staff to run the floor. Aldi famously stocks pallets and boxes straight onto the shelf rather than unpacking each unit by hand — a practice that only works because there are so few units to handle. Labor per dollar of sales drops. Then the number does one more thing, the most lucrative of all: with so few slots to fill, Aldi fills almost all of them with its own brands. About eight in ten units sold in Aldi's US stores are private label — against 30% at Walmart and 27% at Kroger.⁶ Aldi Süd runs roughly 90% private label.⁴ Owning the brand instead of renting shelf space to a national one means capturing the margin a manufacturer would otherwise take.

Why an incumbent can't just shrink its way over

Here is the part that makes it a moat rather than a clever tactic. The advantage isn't a thing Aldi has — it's a thing Aldi is, and the same structure that makes it cheap for Aldi makes it ruinous for anyone large to copy. A national grocer's supplier contracts assume it carries the long tail; its real estate is sized for 30,000 items; its customers come because there are eleven ketchups. To match Aldi's cost base, the incumbent would have to gut the assortment that defines it — and the moment it does, it stops being the store its customers chose. It cannot move halfway. Carrying 15,000 items gets you neither Aldi's buying concentration nor the full-selection promise; you've paid the cost of cutting and bought none of the benefit. The constraint that liberates Aldi imprisons the people who would chase it.

That is why Aldi's expansion reads less like a competitor entering a market and more like a different organism arriving. It operated 2,428 US stores across 39 states by late 2024, even as it absorbed and then resold pieces of a conventional chain it had acquired.⁸ It plans 800 more US stores by 2028 on roughly $9 billion of investment.⁷ Each new box drops in pre-loaded with the entire cascade — the buying power, the private label, the lean labor — because the model is the store, not something layered on after.

Isn't this just a price war Lidl could win?

The honest objection is that none of this is proprietary, and one rival proves it. Lidl runs the same hard-discount playbook — limited assortment, heavy private label at around 75% — and actually out-earns Aldi, posting €125.5 billion in 2023 turnover to Aldi's €112 billion.⁴⁷ If a second company built the same machine, how can it be a moat? Two answers. First, a moat doesn't have to be unique to be durable; it has to be hard to cross. The fact that the only credible challengers are other hard discounters running the identical structure is the point — incumbents from the 30,000-SKU world remain on the far bank, unable to follow. Second, Aldi's defense isn't 'no one else can be cheap.' It's that within its own format, every cost lever already runs at the structural floor, so a price attack lands on a base nobody carrying a long tail can sustain. Lidl can match Aldi. Kroger cannot — and Kroger is most of the market.

Aldi began in 1946 as a single store the Albrecht brothers took over in Essen, and grew into a discounter on a model so simple it's easy to mistake for an absence of strategy.¹ But the empty feeling of an Aldi aisle is the most strategic thing about it. The 28,500 products it chose not to sell are doing more work than the 1,500 it does. The genius was never the quarter in the cart. It was deciding, once and structurally, to sell less — and discovering that less, compounded across every other cost in the business, is the one advantage a giant cannot shrink its way into.