why isn't the use of the bidet more widespread?

I have a theory. Almost every hot country I've been to has bidets. So you have to ask yourself why? Well I'll tell you. After I moved to a hot country (Spain) I realised that if you don't use a bidet and go about your day, the shit in your ass will begin to liquify and you will get very itchy. This is not good. This also doesn't happen in countries with a more temperate climate. That's the reason, I think.