Thousands of remarkable goals are scored every year and almost none remain widely known a generation later. The survivors have properties that make them easy to retell.
A goal that can be described in one sentence survives
Stories pass between people verbally long before anyone finds footage, and a goal that needs three sentences of context will not make the journey.
A run past several players, a strike from an impossible distance, a finish from an angle that should not work: each compresses into a phrase.
Complex team goals with six passes are frequently better goals and are far harder to carry, which is why they fade despite their quality.
The stakes have to be legible to someone who was not there
A goal in a final or a tournament knockout carries its own explanation, because the importance is obvious without knowing anything about the season.
A decisive goal in a league match requires the listener to understand a table, a run of form and what was at stake, which most will not.
Consequently the surviving goals cluster heavily in major tournaments and finals, and league soccer is underrepresented relative to how much of it is played.
Footage has to exist and be good enough
Goals from eras with limited camera coverage survive only if a usable angle was captured, and many notable ones simply were not filmed well.
The available angle then shapes the memory, since everyone who discusses the goal is describing the same shot from the same position.
Modern goals face the opposite problem, with so many angles and so much footage that no single image becomes the definitive version.
A named player carries the goal forward
Goals attach to reputations. A great strike by a player with a long career is retold within the story of that career and stays in circulation.
An identical goal by someone who left the sport shortly after has no vehicle, and it disappears with the season it belonged to.
This is unfair to the goal and entirely predictable, since what is being preserved is a narrative and the goal is one of its episodes.
Anniversary coverage does the actual maintenance
Broadcasters and publications rebroadcast famous goals on round-numbered anniversaries, which reintroduces them to viewers who were not born at the time.
That process is selective, and each round of coverage narrows the field further toward the handful of goals already best known.
Fame in this sense compounds, and a goal that missed the first two anniversary cycles is unlikely ever to enter the canon regardless of how good it was.