"If I get better, they might give me more!"
It's true that this kind of improvement isn't for everybody. If you're one of the few who is moving further, faster...then pick a reason and move!
1. Get better at what you DO do so that you can move on to other things of equal or greater interest.
2. Get better so that you can spend time with other people who are getting better. Get everyone to push on each other just a little bit more!
3. Get better and look back on what "used" to be a bigger deal. (I love looking back on notes and to-do lists from the past couple of decades to think, "I used to worry about THAT?!?!?"
What about you? Why get better?