No one understands what a bidet really is.
In the old days, they were a separate free-standing device. Not a lot of people have space or money to add one of these types of bidets to their bathrooms
Now they make them as toilet seat attachments that don't require extra space and really aren't that expensive.
But people don't know. Older people will be like, "Oh a bidet? No I don't want another toilet like device in my bathroom"
So that gets rid of all those people.
Next you have the people that know about the new style bidets that's just a fancy toilet seat.
Their biggest deterrent is probably cold water. Spraying cold water on their butt doesn't appeal to most people.
You can get bidets that heat the water, but you have to have power behind your toilet, which not everyone has.
Then you have older people that just can't work them or don't feel like they can. Like my grandfather, I installed one with all the bells and whistles for him. Yet hitting a button and doing all that was too complicated. He was 90+ and could barely use a cell phone for basic functions. But he'd rather wipe his butt like he knew than mess with the "complicated" bidet.
Eventually everyone is going to own a bidet, it really is the way to go.
We just aren't there yet.