I think one reason they don't make that kind of leap is that the major diaper manufacturers are already in constant hot-water, due to the environmental impacts of their products, and that there seem to be far more non-special needs children wearing diaper past the usual age, even starting kindergarten and first grade still wearing diapers, so if KC or P&G were to produce even larger sizes than they do know, they'll get shit-on by critics saying that they're just doing it to keep children in diapers as long as possible, so they can make as much money as possible, rather than actually trying to meet the needs of people/children that legitimately need such a product.