What about Zappos? Isn't that a counterexample ?
Zappos may be in retail, but they are not low margin. Their gross margins (revenue - cogs) are roughly 35%. Compare that to Nordstrom - 37.5%. And coincidentally, Nordstrom also has a reputation for good working conditions.
Best value: virtually always. Lowest price: not as often as you think.
I think part of the reason I got my job is because I euphemistically referred to "successfully implementing technical solutions in a complex political environment", and everybody knew exactly what I was talking about.