It is imperative to mention the development of forces and means of Electronic Warfare (EW). In the Russian Federation, this direction was developed back in Soviet times, and our potential enemy, the United States, relying on its isolation, did not develop this type of modern war. If we recall the case with the USS Donald Cook destroyer in the Black Sea, when our SU-24 knocked out all communications and radar systems and the ship was left blind and dumb, then this type of struggle promises to be very promising. Moreover, the development of electronic warfare goes to the space level in order to create interference or "substitute" images from satellites of navigation systems. If this can be done, then all weapons that are guided "from memory" and / or with correction via satellites will not reach the target and only one name will remain from the high-precision weapon. For example, 10-12 correction zones are laid in the memory of cruise missiles so that the deviation from the target does not exceed 50 m. In case of violation of the correction channels, the deviation from the target can be calculated in kilometers.
It is also worth saying about the development of unmanned vehicles intelligence and destruction. Modern drones can already carry 2-4 air-to-ground missiles and, based on the picture on the monitor, accurately determine and destroy a potential target (for example, a car with a supposedly commander of a bandit formation). For several years in the United States, there has been a discussion between "nerds" and special operations forces: who is more effective in intelligence and sabotage missions, and is it worth risking highly professional people whose life and training cost millions of dollars. The development of this type of weapons will make it possible in the (distant) future to do without pilots of combat aircraft and helicopters.
Another promising direction is the creation of "smart division". Principle: the movement of military units, all management, control, evacuation, logistics, the use of weapons, etc., etc., etc. are tied into one system and carried out from one command post. This requires a breakthrough in all directions: communications, weapons, control systems, movement, etc. For example, for soldiers of such units, small arms should be created according to the principle: "fire - forget", controlled from the command post. Those, for example, in the course of a ground clash, a fire weapon is determined from which it is possible to most effectively hit the enemy fire weapon (for example, this is an automatic rifle of a Marine N). The command is given to the Marine: to take such and such a position and, without visual contact with the enemy from cover, shoots "into the air" (conventionally), changes position, and the bullets themselves aim at the target, the drone evaluates the result of the attack, makes adjustments, etc., etc. This principle develops the strategic and tactical schemes for the use of the types and types of the Armed Forces developed in the last century: the Air Offensive Operation (VNO), the Air Space Offensive Operation (VNO) and the conduct of hostilities in a limited theater of operations based on the use of battalion and divisional tactical groups.
Ending,I can say that in each type of the Armed Forces, hard work is underway to create "weapons of the future" and the principles of their use. Here you can describe for hours on each species. But! In a modern war in a limited theater of operations, the winner will be the one who has the appropriate grouping of forces and means "on time", in the right place, and this is the task of developing means of transferring, transporting troops and, as the experience of recent local conflicts has shown (Chechnya, Georgia, Ukraine ) this is what brings victory. And this is not a type of weapon, we must not forget about it. I would also like to add that even with the unconditional superiority of one army over another, you can always find tactical actions that negate the superiority in weapons and equipment. As the experience of Afghanistan, the fight against Daesh has shown, with all the already existing superiority of the equipment and weapons of the coalition, the United States, the Russian Federation over the bandit formations, the success of the level at which we could say that irreparable losses were inflicted on the enemy, the territory was liberated from phase of the military operation, you can proceed to the phase of police operations to establish and maintain order. Therefore, answering the question about the balance, I would say that no superiority in equipment and weapons will give an unconditional advantage in an armed conflict for many long and long decades, even the entire 21st century.
In fact, making forecasts is difficult. Each new war goes on in a new way. If the capabilities of the weapon are well known, it is likely that these weapons, having lost the secrecy label, have already lost their relevance for the customer.
Before the Second World War, there was a flashy T-35 tank, large and with 5 turrets, it impressed onlookers, demonstrating its power. What is his role in the war? zero.
Before the Second World War, cavalry was considered an extinct branch of the army, but it turned out that (at least on the eastern front) it was very effective. Throw infantry at tank speed through forests and mountains, and on the grass. The Germans invaded the USSR with an incomplete brigade, and ended up with four kav. divisions and a separate Cossack corps.
Technological superiority has already made adjustments to the balance of power.
Regarding weapons, it is difficult to say for sure, however, perhaps the balance of power will change even more when the US and other countries (EU countries, Russia, etc.) have a railgun (electromagnetic gun).
In 2005, the US Navy began developing rail guns (the program was named Velocitas Eradico). By 2020, these guns should go into service with destroyers under construction. The tests have already been carried out. This weapon is capable of delivering a projectile weighing 10 kg over a distance of more than 200 km at an average speed of about 2,000 m / s. Perhaps the tool is already performing better. An extremely dangerous weapon for any purpose.
It cannot be ruled out that in developed countries, robotics will take on a large role in military operations. And the infantry will remain in the form of the most elite units and will be dressed in exoskeletons.
Obviously, backward countries will become even more backward and unable to resist such armies. But this is only a subjective assumption.
Anyway: "War has changed".