I hear this a lot, but why is it a problem? For most people I encounter ephemerally online, as long as I can't tell the difference, it doesn't matter. If you were an AI, I wouldn't mind. I usually talk to such people to try to understand ideas better and if an AI could provide that, then no problem. If you want some sort of real-world interaction with them, there's a good chance that'll never happen with a real person either. I've had many online friends who I never met but I still felt like I knew them. The AI just has to be good enough never to burst the bubble.

Then there's the opposite problem that we already have to deal with - real people who are effectively AI and not capable of forming a mutual relationship with you, such as narcissists, people with dementia, and celebrities. People can spend years of their lives having a relationship where the other person only really exists in their own mind. Actually it's quite normal to build an internal imaginary model of the people we know which might not actually be correct.