To the extent that this is based on game theory, it’s probably worth considering that there may well be more than just 2 civilizations (at least over timescales of hundreds or thousands of years).
As well as Earth and Mars, there may be the Moon, Venus, and the moons of Jupiter and Saturn (and potentially others, maybe even giant space stations). As such, any unwarranted attack by one civilization on another might result in responses by the remaining civilizations. That could introduce some sort of deterrent effect on striking first.
To the extent that this is based on game theory, it’s probably worth considering that there may well be more than just 2 civilizations (at least over timescales of hundreds or thousands of years).
As well as Earth and Mars, there may be the Moon, Venus, and the moons of Jupiter and Saturn (and potentially others, maybe even giant space stations). As such, any unwarranted attack by one civilization on another might result in responses by the remaining civilizations. That could introduce some sort of deterrent effect on striking first.