There are economics papers about ‘the vanishing middle’ that explain why products go bimodal. (I can’t find them right now; google-foo is failing me.) The gist

There are economics papers about ‘the vanishing middle’ that explain why products go bimodal. (I can’t find them right now; google-foo is failing me.) The gist I remember is that people lock onto a single differentiator: normally cost or quality. This moves most of producers to those outside points. Companies ‘trying’ to stay in the middle end up being more expensive (on a cost/quality measure) because they can’t reach mass production as easily as either the cheap or fancy.