Slow breakdown scenario

[Tarrel]

History shows that civilisational collapse often takes a long time. From the heights of the Roman empire to the depths of the dark ages took several hundred years. In "The Long Descent", John Michael Greer likens it to tumbling down a mountainside in fits and starts rather than a straight downward plummet.

FWIW, I don't really see our preps as being used in some sort of end-game (although that's perfectly possible), but more to give us support during tough periods, to be replenished in better periods of the long collapse. Sort of like a battery is used with an intermittent renewable energy system to give constant, reliable supply.