I was moved onto a new team a 5 years ago because they were struggling with not being able to complete their Front End Dev projects. The work on this team is drastically easier than what I used to do, but my new boss has always stressed wanting me to help others get better and improve. Fast-forward 5 years. All of the people I've helped train, are leading their own projects now and doing well.
However I am left with one colleague who after all this time is still stuck with very basic knowledge, and is unable to do her job without constant help. She is an old friend of the boss, and has been written up countless times for not doing her work, however my boss still insists on me working with her to help her improve.
My team has been pushing more and more difficult projects on me this last year, and I'm finding that after all this time of helping others, I have stunted my own growth so much as to where in my eyes, I feel I am still a strong "worker", but now an incompetent "developer". After all our sitdowns we've had with my colleague, my boss is a very nice guy, but I don't feel like my boss will do anything aside from having another 'sit down'.
How do I bring this up to him, or is it best to just leave, and learn on-the-job elsewhere?