When I do work - I explain to my client that there is no need for my service "to install something" and refer them to less experienced devs who does major work

When I do work - I explain to my client that there is no need for my service "to install something" and refer them to less experienced devs who does major work and client invites me to fix something specific, or architect things or something like that. End result - less time billed and more cost effective work. In the same time other developer can learn stuff and gradually progresses to more advanced level. Contrast this to any handyman or plumber - they always seems to charge $50+/hr and $75+/hr no matter how simple task is at hands. And I bet if I had to deal with serious stuff, this rate would only go up. I.e. what they do is comparable to installing wordpress for $10/hr work. This is my problem.