As an example of military technical development being driven as strongly by cultural as by practical reasons I submit as a prime example the SINGLE SEAT F-22.

A large portion of the Air Force believes that a real fighter is flown by a single fighter pilot. If it is operated by a crew of two it can't be a real fighter. The F-22 was designed to be an air to air fighter so it would only have one seat and that was that.

So we have the most expensive, most complicated fighter in history; with the most extensive set of systems, sensors and weapons ever installed on a fighter and with previously unimagined aerodynamic perfomance being operated by one pilot. That pilot has fly the airplane, keep track of all the data, operate the systems and watch the world around him all at once and all by himself. When the day comes when the enemy makes it through to visual contact with the F-22 the pilot won't even have someone there to look out the back for him.

The airplane would be vastly more effective and have more potential for growth if it was a two seater. But, then it wouldn't really be a fighter.