The most obvious explanation — that the song is simply very good — is both true and insufficient. There are many very good pop songs from 1987 that have not accumulated 1.7 billion YouTube views or become the vehicle for one of the most widely propagated internet pranks in history. Musical quality is necessary but not sufficient to explain the song’s specific trajectory.
The rickrolling meme is the most obvious contingent factor — the specific historical accident that took a moderately well-remembered 1980s hit and turned it into a universal cultural reference. Without the meme, “Never Gonna Give You Up” would likely have followed the trajectory of most SAW singles: collected by nostalgia audiences, included in 1980s compilations, heard occasionally on radio stations dedicated to the decade, remembered fondly but not actively. The meme created something different: an active cultural presence that is constantly renewed by each new instance of the prank, each new person who encounters the video for the first time in a rickrolling context, each new deployment of the song in a comedic or celebratory context.
But there is also a musical argument for the song’s durability that is worth making. The vocal performance — the voice that stopped Pete Waterman in his tracks in a Warrington nightclub in 1985 — is genuinely arresting in ways that transcend the specific sonic clothing of 1987 pop production. The deep baritone has a warmth and a certainty that the song’s declarative lyrical content — promises of loyalty, devotion, the refusal to abandon — carries with conviction. The message of the song, delivered by that voice, sounds like something that means what it says.