That's a great reason to go into management. I also was in a position where I felt there was nothing else to learn as I could just build the same thing over and over. I moved into a different technical area instead.
I used to write animation, physics and AI code for video games. I got the point where I was just moving company to company and writing the same system. What I moved into was still video game related but server side. This way I had to learn a whole new set of skills and a new knowledge domain, which brought challenge back to the job. But in addition I had been changing as a person, and I fit in better with server guys and execs than game devs.
I also don't want a management position and plan a technological move. Are you happy with what you did?