I’m sorry to say this but it seems like you don’t understand that not all people who use internet are IT people. You don’t seem also to understand that not all individual categories of professionals that are unrelated with IT technologies, are registered in any lists or in any statistics.
Visual artists are everywhere. Do you really want me to give you a source that says that they are millions? Isn’t a single search enough to make you realize it? What sort of attitude is the one who says that if something isn’t listed somewhere it simply doesn’t exist?
Artists have to have websites for PR or publicity purposes but they are not web designers and they don’t have any particular preference on whatever regards the cms platform they use, they are usually struggling financially in order to be able to pay for the services of a professional webdesigner and they go whererever they are offered something that can work easy and for free.