The two proposed theories are “deception” (hiding the age of the movie) and “convention” (it’s how everyone else does it, so we keep doing it that way). General

The two proposed theories are “deception” (hiding the age of the movie) and “convention” (it’s how everyone else does it, so we keep doing it that way). General consensus seems to be the deception theory is nonsense and the convention theory is pretty obviously correct (and I agree). The next interesting question is why the convention persists. One theory that works for things like monuments might be “gravitas”: it’s harder to decipher the date, but monuments are important and sacred, and we signal our respect for that sacredness by accepting the extra decoding cost. That theory does not work for copyright dates on movies, there is nothing sacred there. However, there is also no pressure on the copyright date to be readable and informative. Approximately nobody needs to be able to tell the copyright date of a movie from a glance during their credits roll. So there is no cost to imitating gravitas and no reason to stop; in such a frictionless environment, the inertia of the convention is, by itself, enough to keep the practice going indefinitely.