Well, one reason
I've heard much of the reason for the soap statistic is that the French prefer a harder soap than much of the rest of the West.
You've heard the story of why soap is the way it is, haven't you? The makers of Ivory soap accidentally left a batch stirring too long. The stuff it made was light and fluffy. They tried pouring it into molds, anyway, rather than just toss it. It was still "soapy," but really light, and dissolved really fast. Hmm, same volume, cheaper shipping, faster usage ... Brainstorm! Now we just need to figure out how to market it. Hmmm ... Ahh: "99 and 44-100ths percent pure. It floats!"
The same ingredients, assembled without the extra-vigorous mixing, could make a bar about three times denser that doesn't dissolve so quickly. And the bit about purity having anything to do with floating? Pure BS.
