What weapon systems have come and gone very quickly?

The atomic bomb was used twice, four days apart, with major effect.

It has never been used in-theater since.

Despite not being used for the last 75 years, it continues to cast a large geopolitical shadow.

Here is a chronology of infantry weapons that became dominant, and then were superseded, over the modern time period in fairly short order.

• The Pike is revived in Europe about 1300 and hits its heyday about the Thirty Years War, exemplified in Cromwell's New Model Army of about the same time period. Dominance is a bit over 400 years (1300 - 1710)

• The smoothbore musket completes its replacement of the pike on the battlefield with the widespread adoption of a spring-loaded slot bayonet that prevented it from falling off invented about 1703. Dominance is about 150 years (1710 - 1860).

• The single- and double-shot breech-loading rifle with self-contained powder, primer and bullet attains dominance over breechloading firearms in the 1860's in both Europe and America. Dominance is about 25 years (1850-1875).

• Repeating rifles starting with the Winchester Repeater of 1873 provide the infantryman with semi-automatic fire capability. Dominance is about 75 years (1875-1950).

• The automatic Rifle is rare - essentially an artillery weapon fielded by privileged infantrymen or teams - until about 1950 when it becomes ubiquitous on the battlefield. The obstacle to more rapid wide deployment earlier is likely logistics - the difficulty in supplying sufficient ammo to the field for an infantryman who in most circumstances prefers automatic fire to anything slower. Fully automatic rifles with capability for semi-automatic and single-shot fire remain the ubiquitous infantry weapon on the battlefield today.

The lance was revived across European cavalry through and in the wake of the Napoleonic wars, becoming ubiquitous as a light-cavalry weapon in preference to the saber by the Crimean War. The summer campaign of 1914 with the widespread adoption of entrenchments in the wake of the Battle of the Marne made non-dragoon cavalry obsolete in a season. Dominance about 100 years (1815-1915) as a light-cavalry weapon.

One can well argue that the rapid development of fighter aircraft in World War One encompasses at least three distinct generations of weapon system, each one of which made the previous completely obsolete (ie a death trap). Even in WW2 one would not want to be flying in 1944-5 with a 1939-40 fighter, even when the plane name (ie Spitfire Mk 1 vs Spitfire Mk V or VI) ostensibly remains unchanged.

The turreted fighter aircraft.

Various turreted fighter aircraft were introduced at the start of WW2. By the end of WW2 all were obsolete and no new designs had been built.

Air power keeps turning to high speed, high flying aircraft, the idea being to simply fly so high or fast interceptors and/or ground based defenses can't reach or catch them. This doesn't mean they had to fly faster and higher than contemporary interceptors, rather they had to fly fast enough and high enough to get in and out before they could be intercepted; the reaction time of the defenders was a factor, plus the climb rate and range of the interceptors. It's an idea which waxes and wanes as fighter and bomber technology chase each other, detection technology got better, and reaction times got faster.

In early WW1 fighters could not attain the altitude of a bomber or Zeppelin rendering them nigh invulnerable. This lasted a few years before but rapid improvements in fighters rendered them obsolete.

The interwar period saw the Schnellbomber (German for "fast bomber") concept. It was thought a fast, sleek, twin engine medium bomber stripped of defensive armaments would simply outrun fighters, or be in and out before the enemy had time to react. At the time fighters were slow, single-engine biplanes, and air defense was uncoordinated. But rapid improvements would quickly render the Schnellbomber concept obsolete by 1940. Many of the Luftwaffe's early bombers were designed as Schnellbombers and later pressed into service as conventional medium bombers; in particular the Ju 88, their most numerous. The only really successful Schnellbomber was the de Havilland Mosquito able to maintain a speed advantage over contemporary interceptors until jet and rocket aircraft appeared.

This would return post WW2 in aircraft such as the B-36, B-47, B-52, and B-58. Again, the new bombers were to fly faster and higher than conventional interceptors and anti-aircraft artillery. Jet interceptors and the introduction of surface-to-air missiles pressed them ever higher and faster culminating in the in the Mach 3 B-70 and B-1. When a high flying U-2 spy plane was shot down by SAMs in 1960, that heralded the end of extreme altitude as one's sole defense. The B-70 would be cancelled and the US would switch to low altitude, subsonic bombers relying on electronic warfare and ground clutter. Though some tried to keep the idea alive with the B-1 for decades.

The idea of strategic bombing would be largely supplanted by ICBMs, submarine launched nuclear missiles, and cruise missiles.

The "high and fast" penetration tactic lasted about 15 years from roughly 1946 to 1961, but two very successful remnants hung on.

SR-71 Blackbird, while not a bomber, carried the idea of high and fast to an extreme by cruising at Mach 3 and 20km high. It remained able to fulfill its role reconnaissance aircraft well into the 90s. While never again quite as immune as the U-2 was, with careful mission planning it could gather intelligence deep in hostile territory.

While the high flying bomber only lasted 15 years, the B-52 originally designed as one has lasted 65 years with no end in sight. Originally designed in 1946 it has been in continuous service and adapting to new trends since 1955. Originally designed as a high flying strategic bomber, it adapted better than all of its contemporary US heavy bombers into the new low flying, subsonic role, later from nuclear to conventional bomber, and then from high to post-Cold War low intensity conflicts.

Another example is the torpedo bomber: an aircraft used to launch anti-ship torpedoes. These were used between 1914 and 1945, but were made obsolete by anti-ship guided missiles.

Missiles could be launched from much greater range, greatly reducing the risk to the aircraft and its crew from the target ship's defences. Since homing torpedoes did not exist until late in WWII, and were still new and unreliable at the end of that war, torpedo bombers needed to get close and to fly straight while dropping their torpedoes, making them very vulnerable to anti-aircraft guns.

One can argue that battlecruisers... lightly armored fast capital ships that carried battleship grade main guns... had a short lifespan. They were popular in theory in the naval arms race prior to WW1, but the substantial number of battlecruisers lost at Jutland showed the deficiencies... they weren't fast enough to avoid being hit. The loss of battlecruiser HMS Hood to a single hit from Bismark finished them off for good, although big gun ships in general were on the decline by then, due to vulnerability to air attack... as was shown with Bismark, shortly after the loss of Hood.

The dirigible as a bombing platform had about a two year lifespan, from the first use of them in 1916, to being discontinued as bombing platforms by Germany late in 1917 due to extensive losses. The British had figured out how to set them on fire.

Poison gas also had about a two to three year lifespan, in WW1. It's decline wasn't due to countermeasures, but general revulsion of the concept by most nations after WW1. While poison gas attacks were considered in WW2, and stocks of gas shells and bombs were on hand, they were never used.