I have no idea. I’m still burning bright and fully up front and in focus.
Can’t imagine burning out _or_ fading away.
Think of music as to why this question is illogical to me.
You have to find your pace. Neither burning out nor fading away.
Song have can have fast points, slow points, quiet points, loud points. Patterns can be foreshadowed early on and come into full focus later, or later patterns can be changed echos of previous patterns.
Now think of a jam band. They can play for minutes, hours, or days if they have enough people to switch out the instruments to take breaks and sleep, so that the song never ends.
In theory you can have a single song that plays forever (practically speaking).