Oh, there ARE such avatars, but the problem is in the degree of execution of them. In the SF Bay Area a year ago some guy 'cloned' his now dead fiancee digitally and had it 'talk' to him via messaging. It was of course just a dead puppet. The digital avatars you mention are not based on strong underpinnings. They do not have a true Self inside, no soul, and no ability to be a true avatar. Just chatbot hacks. In a way it is like some actor plays a doctor on TV, but the actor has no ability whatsoever to heal the ill. He just wears a white lab coat and looks purposeful. A chatbot could talk about getting laid, but it never has had sex and cannot understand the experience.