The original meaning of Black Friday appears to be the day on which retailers begin to turn a profit, going from “in the red” to “in the black,” due to a massive increase in store volume.

The sequence and causality seems to have reversed with time, where the objective is now to drive massive volume increases with unprofitable pricing, as an investment for the longer-term.
The difference however isn’t a change of goal, but of tactic… the motive is still a profit motive, only the timeframes, means, and magnitudes have expanded.
Retail is not only consumer retail, consumers aren’t only shoppers, and shoppers are also, in a sense, traders… The demand-side objective is to select and time the purchase for maximum near-term value, while the supply-side trade is long-term oriented.
The settlement price reflects differences in tactics and timing along the chain…

… and the result is sometimes but not always win-win.