What the computer did was not eliminate publishing, it made it easier and much, much cheaper. Anybody could do it and just about everybody did do it. The prediction today is that the Internet will eliminate printing and publishing. That prediction may be a little closer to the truth than intergalactic travel, but how much will be judged by posterity. There are many media that are in print because there was little or no other choice when they started.
Printing is expensive and so is mailing.
Encyclopedias and newsletters, for the most part, are better served electronically. On a CD or on a Website, or both, research is quicker and access easier and cheaper. In other media, the Internet only serves to accompany, at least for now, the printed version. Catalog shopping, for instance, has benefitted greatly from the Internet. LL Bean, Land's End, etc, still want to send out catalogs to entice shoppers, but with the Internet they need to print and mail many fewer, and the catalogs steer shoppers to their Website, where their whole inventory can be accessed.