Mensa Boy and mini-MB call foaming hand soap "Scam Soap."
MB's theory is that it is not more cost-effective than regular liquid soap. Apparently that's been part of the marketing? I can't really confirm that. I don't pay close enough attention to that kind of thing.
Anyway, at MB's work they have dispensers in the restrooms for both kinds...foaming and regular liquid soap. He says the foaming ones are always emptying faster than regular ones.
My thinking is that people might be gravitating to the foaming soap because it's lighter and rinses off faster.