Interesting. I have a half boxworth of Lux flakes on the shelf by my washing machine. Ever since washing machines got a wool setting I've not done any hand washing, so it's been there untouched for a while now. Says "Lever" on the pack.
"That’s why we’ve developed a liquid variety that has all the benefits of dry soap flakes with none of the disadvantages"
Ah so not down to being able to sell you the water to take home with you too, then. I reckon if the market and the will was there they could get a new machine commissioned to flake soap.