And this is where the trouble starts. Nike’s incestuous strategy was bringing in data on existing customers — those whose behavior didn’t need changing.

Letting data drive you is fixed-mindset thinking
“A fetish has been made of quantitative methods and whole laboratories have been devoted to solving, with elaborate statistical machinery, problems which had very slight importance.” — Gregory Bateson, 1944

It’s tempting to reach only for the data that’s easiest to harvest, and stop there. That’s exactly what Nike did with their online shopping data. As a result, their product priorities rapidly diverged from the kind of things ordinary customers buy, while product with mass appeal rotted in warehouses for lack of places to sell it. And the longer Nike chased these fringe customers, the more ordinary shoppers moved on to a competitor’s product