This is a very interesting topic.
I am one of those people and I experience the exact same result - companies get dependent on me. I agree with Nitin that it should not be my problem. Most of the time it is the users that do not want to go through the effort to fix something themselves - it is sometimes just easier to ask someone else (being me most of the time). My current client makes an effort to force me to educate their employees (and implement the correct tools) to do all the work themselves and as far as possible I am empowering them to do just that. This, however, is sometimes reliant on me having enough time to set such processes in place. I caught myself often that I will do a menial work for the client for very lengthy times before I can either automate it or help the employee/s to do it themselves.