As a teacher, I can think of no greater achievement that developing students that surpass me. Of course, I will give them one hell of a run for their money to try and catch up to me....
I don't teach Aikido but I do coach. I never made it past "club" and "college" level in either Judo or Rowing, but people whom I've helped learn their rowing basics have far surpassed anything I've done.
Do I live vicariously through them? I hope not. Do I cheer their accomplishments? YOU BET.