“Today’s diapers are small miracles of industrial science, the experts say. They are softer, thinner and longer lasting than ever before, not by accident, but because companies like Procter & Gamble and Kimberly-Clark have poured billions of dollars into research and development. Like tech companies, they’ve put a premium on transformative ideas.” That’s good news for your baby’s bottom. But bad news for your bottom line. Especially if you’re among the one in three families that can’t afford diapers.