You see there is no economical global wireless service to search the internet or information. In fact there are places without electricity. These constraints pretty much limits devices like mobile phones and net books and without electricity even electronic readers are worthless. At that point the value of a self contained book with everything you desire to know about an area is very valuable. I recently paid $70 for three guidebooks to Colorado. Some may question that logic because probably 85% of the routes are available free on the internet. That's true but as has happened more than once people print the route information for a climb and only read the descent information once so they have an adventure descending easy terrain that was more scary than the route itself. Also in the case that you are holed up in a location without internet access you may want to climb another route or do something else. With a guidebook you will have a number of options of things to do in that area whereas otherwise you may have no idea what to do.
Additionally there are usually those few routes or activities in the book that are not online because they are obscure or infrequently done. I know that several times while my family was on vacation we would stop at places where we were the only tourists. In fact it has happened so many times it isn't even strange anymore. We have also stopped at those national monuments that get only a few thousand visitors a year and we were one third of the groups there.
So there is still value in a guidebook. Something that does not need recharging or a wireless signal. A one time purchase with no residual costs.