Condorito/WMG

Each time a character commits a "¡plop!", the universe continuity is reset.

That would explain the complete lack of continuity from a joke to the other and how we can seen them in different time periods, even. The few jokes that don't feature said Face Fault (mainly the early 50's ones) do feature some kind of continuity, until a joke with a "¡Plop!" appears.