Get great on your own time, so you're ready when the big moment arrives.
No one imagines that a basketball player can achieve the pinnacle of their sport by just playing in the games. No one imagines that a pianist is going to get great only by playing concerts every day. We all need to train, practice, and hone our craft. And it's not sufficient to do that in the heat of the match.
If you want to be a great speaker, practice when you aren't in front of people. If you want to be a great entrepreneur, work those skills outside of the board room. If you think you're “too busy doing” to be training, then it's time to shift priorities or suffer the ceiling that will come from not practicing in a controlled environment.