Every winning strategy is repeated and expanded until the point where it becomes a losing strategy. (A little longer, even , because there is a momentum around the expansion phase, and recognizing the returns have swung negative is not immediate.)

This has always been true.

What may be new is the pace: a winning formula can be taken nationwide, netwide, worldwide faster than ever before. So it also reaches its points of diminishing returns and rising countermeasures sooner. The utter dominance of the Starbucks model can be followed almost immediately by its exhaustion.