The Seattle Seahawks could’ve withstood a predictable loss to the San Francisco 49ers if other results went their way.
Generally speaking, the majority of the results went against them.
Wins by the Green Bay Packers (on Thursday), Los Angeles Rams, and Atlanta Falcons all resulted in those teams improving to 5-6 on the season. The Falcons actually took the lead from the New Orleans Saints in the truly awful NFC South, but it dropped the Saints to 5-6 and in the thick of the wild card hunt.
Seattle had multiple games on virtually the whole of the non-wild card teams just a few weeks ago, but now it’s just a single game.