It is difficult enough just keeping up with the changes in the practice of medicine, let alone finding the time to become computer literate. Another is financial. Many practices expenditures are governed by groups, who don't want to spend the resources to get their physicians on-line. A significant factor is fear of the unknown, of the technology, and most of all of appearing to be less than an expert in a given area, e.g. being ignorant. Several of my colleagues admit to suffering from computer-phobia, being apprehensive of turning a computer on, thinking it might blow up, or worse, crash during use.
Many physicians lack the basic typing skills needed for operating a computer keyboard.
Others use the computer for personal reasons personal e-mail, playing games, or watching stocks, but not for medical ones. This phobia of computers is pervasive within the medical field. I believe the main obstacle is getting physicians to admit a knowledge deficiency in an area they have never had the time to study. Fortunately, those in the upcoming generation of physicians have grown up with computers and used them in training. Consequently the next generation is much more comfortable with computers, have embraced the new technology and want to use it in their practices.