Of course, real time is a better form of communication. But then, why don't we just stop using emails, just do video conference, or better yet face-to-face mee

Of course, real time is a better form of communication. But then, why don't we just stop using emails, just do video conference, or better yet face-to-face meetings? Because there are other limiting factors. For example, no one has the time to have real-time conversation all the time. Real-time also limits the amount of people you can effectively communicate with. That's why we have email/forum/tweet, because they serve different functionality. Thus, real-time communication will never replace static communication as long as such intrinsic logistic limits exist.