I foresee a future state of the National Football League that is centered around injuries. The games take twice as long because there are multiple serious injuries on every play. The rosters are twice as large because of the need for replacements due to in-game attrition. There are several deaths due to injuries sustained in games every year, which, while bemoaned as tragic, are tolerated. The year? 2025.
It's not too far away from today's game. There is an upper limit on how big and fast football players can get before very serious injuries become more and more frequent, eventually leading to the first in-game death. It will happen, someday, and don't be surprised when it does.
Mark my words.