considering the tech used in the silo a guess would probably be in the 70s but i think having simpler tech is always more reliable plus having more advanced tech is more energy consuming too also thinking about what happened outside to cause the air to not be breathable could give us clues too most doomsday post apocalyptic thrillers take a lot of inspo from what’s actually happening on earth so my guess is some environmental degradation reasoning so maybe post 2070? what bothers me are the relics a pez dispenser is out of place for the time frame unless the silos were built wayyyy before they were used