Mass armies prior to WW1 were 'the schools of the nation' instilling what ever 'national spirit' that the authorities at the time wanted. The man power was there to be consumed in a massive 'make work' sort of exercise. Manpower was cheap, equipment was expensive. You have to move to professional armies to flip that around.
The 1914 Battalion of 1000 rifles being taught the 'spirit of the bayonet' made way for the Battalion of 1918 with 38 Lewis guns and it didn't matter how many rifles were left and the bayonet opened cans. A 1914 Battalion commander would be completely bewildered and lost on the 1918 frontline but a 1918 Battalion commander would recognise many of the battlefield attributes evident today; fire and manoeuvre, supply, logistics, evacuating casualties, air support, cooperation and supply, radio comms etc.
The problem is not technology but leadership. The Navy, the largest heavy engineering organisation in the Empire invented the Tank - turrets, casemates, engines, hatches not doors, deck not floor etc. Even the RNAS took the first armoured cars to France and Belgium and drew up the spec for a strategic bomber. The memo for an independent airforce of bombers was written by an Admiral. No army was going to do something that frightens the horses. It's not really in their interest to innovate if it means just 38 dudes replace the 1000 they use to have.
Extend the naval influence further and look at Rolls Royce. They got into the aero engine market at the request of the Navy but only as liquid cooled engines not air cooled as the Royal Navy wanted. HP went from 250hp in 1915 to 300hp in 1917 for the Eagle series. Similar for the Falcon but the Condor was about 675hp in 1918. This was for a bomber to reach Berlin but could also be any large commercial aircraft to carry a large payload a long distance.
Consider that the Military didn't have the fastest aircraft in the world. They were several years behind the bleeding-edge tech. The other thing that the Military needed was aircraft that had a lifecycle of about 5 years. During war, this compressed down to 1 or 2 years. Having said that, the Military strived for aircraft that were maintainable in the field and easy to fly for the vast numbers of pilots. Without the war there would be a smaller number of more highly trained pilots.
Another thing to consider would be as theories around airpower evolve, what would be banned by international agreement? The Hague convention was held every 7 years and due in 1915. There was already a "Declaration Prohibiting the Discharge of Projectiles and Explosives from Balloons".
In defense of the military mind, it can also work things out for itself without war. The RN is an example, most of the ships required over the 1920's and 1930's had been scoped or prototyped prior to WW1, suggesting that they didn't need war experience to develop. The Lightfoot class leader of 1913-14 was seen as the right size for all future destroyers because it had the required endurance to stay with the fleet for 3-4 day sorties and sea-keeping. It's the same tonnage and dimensions as the later Scott class leader that provided the prototype of most Destroyers built in the 1920s and 30's in many navies.
Without war, the classic 'u-boat' was fully developed and matured by 1914. Compare the German U43 class designed pre-WW1 and under construction in 1914 with the later Type VII refined during the 1920's and 30's:
Type U43 - 725 tons surfaced 940t submerged
Type VII - 769 tons surfaced 871t submerged
Type U43 - 65m long, 6.2m beam
Type VII - 67m long, 6.2m beam,
Type U43 - 2,400 hp 17.1 knots, 1200 hp - 9.1 knots submerged
Type VII - 2,800 hp 17.7 knots, 750 hp - 7.6 knots submerged
Type U43 - Range 9,400miles at 8knots, 55miles at 5knts submerged
Type VII - Range 8,500 miles at 10knots, 80 miles submerged at 4 knots
Type U43 - 4TT 2bow/2stern, 88mm deck gun
Type VII - 5TT 4bow/1stern, 88mm deck gun
Type U43 - Crew 36
Type VII - Crew 44
Type U43 - 164ft depth
Type VII - 750ft depth
As you can see, 20 years of development went into structural improvements following war experience to increase diving depth from 164ft to 750ft. Why? Because concealment as a defense wasn't enough, great depth was required too. The second war showed that great speed at depth was also required and thus the Elektro Boot was required. However, the high speed submarine had been developed in WW1 by the RN - the R class submarine from completely different requirements ie. to ambush submarines.