Consumables were 79.7% of sales in 2022 and 81% of sales in 2023.

2023 was the first year in which DG's margins took a nosedive and profits suffered materially ($10.68 EPS to $7.55 EPS).

In other words, DG was a stock market darling hitting impressive margins even when its sales mix was not far off from its current mix, i.e., even when it was competing directly with WMT and all the others on the sale of consumables. Similar can be said about the years running up to 2020. High consumable sales, great profits and margins.

If a 1.3% change in consumables a percentage of total sales could have such a massive effect on margins, you'd expect it to show up over the decade prior, when DG's sales mix moved from about 71% consumables, up to about 80%, slowly but surely. Margins remained very healthy throughout that entire period.

Does the change in sales mix have some affect DG's margins, going forward? Almost surely. But the significant hit to DG's margins and profits in 2023-2024 are very hard to explain by reference to changing sales mix. Something else happened. Probably a few things.