In some cases however, the author does indeed know better and over time the work of art they are proudest of might become Vindicated by History.
All of the above aside, this trope isn't necessarily as black and white as it sounds.
After various unsuccessful attempts, unification was achieved, creating a great power after centuries of foreign domination and political division.
Also, works intended to deliver a deep, profound, important message have a tendency to come across as Anvilicious-esque, while works written without such concern end up focusing more on the story itself.
Alternatively, writers are as human as the rest of us and, as individuals, can hold different opinions than their fanbase (or what they think is their fanbase); this includes both expectations of audience experience and perceived aesop importance/acceptance.
When the effect is somewhat delayed, see Vindicated by History. Sub-Trope of Murphy's Law and the Centipede's Dilemma and Sister Trope to Creator Backlash (often a good source thereof, too).
Breakout Character is sometimes related, when a specific character rather than an entire work becomes far more popular than was ever planned.