The seemingly forever existence of email might be due to the fact that writing an email is the same act as writing a letter. No matter how much technology we have, people will never stop writing letters. The human biological machine chooses the tools that is most familiar and the path of least resistance to achieve its goal. By evolution, we are machines that are designed to be somewhat efficient in the process of achieving our goals. Find the simplest thing that works and use it to get the job done.