An aggregate piece increase percentage vs a production cost decrease percentage would be more useful. Brands shift to higher and lower quality and price brackets, so unless they're all going up, it's not much of an issue if you don't have brand loyalty. But I think it's likely most all brands of diapers are going up in price since they saw people were willing to pay ludicrous prices for them.
Over 60% of the country lives paycheck to paycheck and probably simply doesn't have the time to do such a thing, despite the obvious environmental benefits.