Human history is practically the history of the military.  On our planet, it is very rare to call a year without a war.  Therefore, wars have been, are and will be, despite our wishes for peace.  Even today, there are many direct hostilities and local wars.  In our time, when the world is stuffed with nuclear weapons, any local war can lead to a global nuclear war, in which the winners and simply survivors will have primitive tools and primitive weapons that will be used again.
 We are not the first human civilization on this planet.  Many millennia ago, people also went out into outer space and even fought among themselves in near-earth orbit.  Then civilizations disappeared for various reasons, and with them their high technologies disappeared.  Do you think that only we are so smart and the Internet and cryptocurrency were invented for the first time?  And if they already existed before?  Now we can answer the question of whether cryptocurrency will last forever.