Computers are wonderful tools, but for most subjects students learn at that point in their lives (middle/high school in the US), computers aren't necessary.
Think about the primary subjects - Math, Science, and Literature/Writing - where do you see the benefits in using computers? Obviously for English classes, having access to computers to type papers is handy, but it's hardly necessary. Computers can be used in math to help illustrate concepts, but you don't want the students using computers to do their work, otherwise they won't know how to do it without them. And much of science is math - again, not something you want students using computers for.
Where there's a will, there's a relative.