Who are these people that, having bought some sneakers already, get a email about other sneakers into their nearly bottomless inbox full of junk (presumedly, given they don't avoid these kinds of marketing messages) will actually notice it amongst the noise and then actually be compelled to buy additional shoes they wouldn't have otherwise (and therefore apparently didn't need)? Certainly they exist in some number, because they show up in optimization dashboards I've built for my clients, but what portion of the market are they, truly? Is this reflective of a psychological disorder (perhaps the underlying cause of "hoarding" is a spectrum-type pathology)? Is optimizing for these customers's odd (and apparently self destructive) behavior the same thing as optimizing revenue in the total market or is it just a local optima that everyone's in a big hurry to to corner themselves in? Even if it was a true global optimum, is it ethical? Is this the microtransaction whale-hunt optimization race to the bottom that mobile games went through (and results in many such as myself avoiding participation in that market) in slow motion due to physical goods' slower cycles?