Pundits have been predicting the advent of the "paperless office" since the 1960s; in the intervening years, the world's consumption of paper has increased rather than decreased.
As you write your report, the first thing you should do is narrow your time scale. There is really no credible way to predict whether humans will use paper 5 million years in the future, or whether humanity as we know it will even exist at that time. Instead, you should narrow your predictions to the twenty-first century, or your own probable life span.
The only way we can predict the future is by looking at current trends. Paper production of newspapers, magazines, advertisements, and letters are decreasing while their electronic equivalents are increasing. While people had predicted that ebooks would quickly replace paper books, in fact the sales of books in paper format have rebounded relative to ebooks, for two reasons. People seem to value paper books as artifacts and prefer the ergonomics of reading them. Second, under current distribution models, ebooks you have purchased can disappear if the provider changes policies; you really do not own the books but only the right to read them for a given period.
Generally, paper is a superior medium for archival storage. We have paper records over 2,500 years old from Egypt while the life expectancy of electronic media is approximately 5 to 10 years. Also, with evolving technology, older electronic media (such as magnetic tape, 8" disks, etc.) become unreadable as the devices needed to read them cease to be manufactured; for electronic media to serve as archival storage, the complete archive needs to be recopied every 5 years. Thus hard-copy human-readable media will probably continue to be used for archival applications and for materials you wish to keep for long time periods, but not be used for ephemeral works such as schedules, advertisements, price lists, etc.