99% of our inventions are made by military people? Well it is true that war has a tendency to move technology forwards, but I wouldn't go that far to say that most inventions are connected to war.
Go look at the time of inventions, the 18th and 19th century. So many of the devices come from the civil sector. So many inventors tried to improve the life, and not the efforts of destroying it.

Also, I don't think it would be a problem to train people to face to face combat nowadays. All you have to insert into peoples mind is pure hatred of the enemies. Think of any modern war fought with extreme methods, like the balkan wars. Just replace their weapons with swords and I garantue you that they will run onto each other and cut their throats. It's a psychological effect of lowering the moral restraints. E.g. the genoiced in Rwanda was mostly peformed by knifes and machetes. And they had a better kill-ratio per hour (sorry for this cold term) then the Nazis during the Shoa.
Being human implies to be unhuman at the best.