I don't think any sort of media can go one forever, and that everything has to end sometime. Let's say that the final apocalypse of Earth is around the year 3,000. Do you honestly think that they will keep making Final Fantasy games for a thousand years? I don't think so. Are popular serials from Roman or even Medieval time still continuing until today? Are even popular series from the 1800s still continuing today?

See, nothing will ever continue forever because it is impossible. It will come to a close once mankind's tastes change, as it always does.