I know exactly what you mean. I run into the same problems. I have been lucky enough to not been let go from any contract yet and I am the one who had to leave

I know exactly what you mean. I run into the same problems. I have been lucky enough to not been let go from any contract yet and I am the one who had to leave for greener pastures usually at the end of contract even though the client wants to renew. I always wished I could get the current client someone to replace me but it is just so hard to do that.