An NFL season lasts only 16 games, but in terms of our memories, it seems to be the only football we can possibly remember. Both fans and analysts alike are subject to recency bias, in which we treat the most recent information we have as the most important information in understanding and projecting a complex game. The NFL moves quickly and has an impossibly high attrition rate. It's easy to forget what happened years ago.
In most cases, though, we can look through history to get a sense of what's likely to reoccur from season to season. What happened in 2018 will stay in the record books forever, but there will be plenty of elements and stories from 2018 that won't happen again in 2019, even if it seems as if the circumstances or the talents involved are staying the same.