We're talking about grocery stores here, not just general retailers. I have a really hard time believing that US grocery stores are operating on razor-thin margins here, given how extremely expensive groceries are (when adjusting for income, other cost of living etc.) compared to e.g. Germany.
One problem of the Austrian grocery store market is that there's just way too many branches per capita (compared to the otherwise pretty similar market of Germany again), which brings down margins.
It is all public information. Plus, logically, it is a low barrier to entry business with zero moat. There are lots of sellers willing to sell for barely above cost.
These are the two biggest grocery only retailers in the US:
One problem of the Austrian grocery store market is that there's just way too many branches per capita (compared to the otherwise pretty similar market of Germany again), which brings down margins.