Well, it's a complicated question, but the ultimate answer is, we're getting there.
The Straight Dope: Whatever happened to the "paperless office"?
A more persuasive explanation [for why the paperless office has failed to materialize], however, is that computers suck. Paper is cheap and adaptable, and, equally important, almost always works. If you’re an office drone scrambling to get a last-minute report out, one disaster you're not living in fear of is the Blue Sheet of Death. Computers, in contrast, make politicians look reliable. And let’s not forget premature high-tech obsolescence.
Having worked in the report-distribution end of the computer room, my own theory is that we just plain feel better if we have our customer data nearby in hard copy. In the old days, replacing a cabinet full of data tables was something you only did every other month or so. With handy, inexpensive computer printers that could print documents far faster than anyone could ever read them, even a small office could generate thousands of pages of new, customized reference data every day.