The US population seems rather stubborn regarding toilet habits. This is anecdotal, but I knew a guy who interned about a decade ago with a company that produces a lot of toilet paper here in the US. He told me that they had internally developed forms of "wet" toilet paper that were pretty much superior to the dry kind in every way (think of the difference in trying to clean off your hands with a dry paper towel and a wet wipe of some kind), and IIRC they thought they could produce them in a way that wouldn't cause a substantial price hike, but whenever they did tests consumers almost universally hated the feeling, and regardless of how much better/easier they cleaned, they basically refused to consider them. Which is a shame, since dry paper really isn't the best cleaning tool...