Shoes that don't fit are difficult to sell

A really long time ago, shoe salespeople noticed that shoes that don’t fit are almost impossible to sell.
This sounds super obvious, but lots of businesses try to sell shoes that don’t fit. Of course people ignore these companies and their urgent agendas. People all they care about is their needs are different than the rest.
One-size-fits-all is a lousy way to market something. Of course some people would be lucky enough to have the right size, but most of the people won’t.
Today people want things that fit their shoe size–their needs. So you either (1) only sell to a small group of people with the same shoe size, or (2) you sell to a diverse group customized versions of your product for their needs. But selling the same size for everybody no longer works.