Chat - Going back in time

I hate chatting on instant messaging system. Sure, they're fine for light stuff:

Kevin: Can I bum a ride home?

Vehicle Owner: Sure, I'm leaving in 5 minutes

Kevin: Perfect.

But when you get longer things and you see something like:

Other Person: Thank you

With a message at the bottom "Other Person is typing a message" and you wonder, "are they still typing? That 'thank you' seems the end. Do I wait? Do I type?" What do I do?

Maybe with the new, modern technology we should go back to "over" and "out" to indicate when someone's finished, sort of like on radio communication. It works there, and chat really is structured like two-way radio, only typing instead of talking.

This would be useful, too, when someone's fired a complex or multipart or series of technical questions at me via instant messaging. Sometimes I can't tell if they're done or still adding more on. And then when it looks like they're done and I begin typing a reply, my replies are usually long and detailed, they start off quickly with "r u there?" because I don't send back an instant, fast but wrong or incomplete answer.

Or they ask one question, I begin typing the answer and then they start sending more before I'm done. How do I then keep my answers tied with the specific, unnumbered, unstructured questions?

At least an "over" and "out" would clarify who's turn it is to talk. Or maybe we need instant message programs to use a token, whoever has the token can talk, and when they're done they pass it. This can keep the conversation structured for easy reading of questions and answers.

On the other hand, I prefer email. For just those reasons. For things with complex answers, email is just a lot easier to keep structured. Questions can be bulleted or numbered, answers along with them. Text can be formatted and doesn't have to fit some arbitrarily small number of characters.

Yeah, much prefer email over chat.