A contrarian (and true) view of the middle-aged:
They achieve a kind of tranquillity, not because they’ve decided to do nothing, but because they’ve achieved focus and purity of will. They have enough self-confidence, and impatience, to say no to some things so they can say yes to others.
From this perspective, middle age is kind of inspiring. Many of life’s possibilities are now closed, but limitation is often liberating. The remaining possibilities can be seized more bravely, and lived more deeply.
In life as in creativity: limitation is liberating.