It appears that the Big Bang came from nothing. EVERY SIMULATION always starts from nothing whenever the simulation program starts running, Our universe has a speed limit. It is the speed of light. That is a fact, but nobody knows the reason why the speed of light is any particular speed and not arbitrarily faster or slower. EVERY SIMULATION also has a speed limit. It is the maximum rate of execution of the program. Life and the various lifeforms appeared suddenly. In EVERY SIMULATION new things come into being, where nothing like them existed before.
You clearly haven't played very many simulation games. Any decent implementation of Conway's Game of Life has an exception to all of your absolute statements, for example.