Zeppelins gained popularity initially because they enabled flying with very large amounts of mass for the time, but their drawbacks were never fully mitigated while planes rapidly improved and surpassed them in practicality.

Flying a zeppelin safely (not even well but just safely) requires not only expertise in zeppelin piloting but also expertise in meteorology due to their extreme vulnerability to high winds and adverse weather. In comparison planes are much more robust and can fly through more extreme conditions. Indeed it took many decades to fully discover all of the weather conditions (like extreme wind sheer / downdrafts) that planes were vulnerable to. Especially in the era before widespread availability of radar and satellite based weather forecasts this was a substantial constraint on airship operations.

Cost is a big factor as well and has a compounding effect on the merits of zeppelins. They require huge amounts of resources to build but also huge amounts of resources to take care of and operate. Mooring stations, enormous hangars, ground crews, etc. A grass strip and a gas station is enough to be a running concern in terms of operating fixed wing aircraft. An improved airfield is little more than a paved road. A hangar capable of comfortably housing a small plane (like a DC-3) is little more than a barn.

All of that adds together and means that fixed wing aircraft operations are easier to setup and get going. But it also means that the characteristic cyclic period of iterative innovations ((re)build, fly, analyze, repeat) is much tighter with airplanes than with airships, enabling a much much faster pace of innovation. And this is definitely evident in history. There were huge leaps in airship design from the turn of the 20th century through the 1930s but these were nothing compared to the improvements in aircraft, especially as you go beyond the 1930s into WWII and the post-war era (pressurized cabins, radar, jet engines, etc.)

In regards to the earlier point about vulnerability it's worth pointing out that the Hindenburg disaster was only one of a string of calamitous big airship disasters around that time period (the R38 crashed in 1921 taking 44 lives, the Roma in '22 with 34 deaths, the Dixmude in '23 with 50 deaths, the R101 in '30 with 48 deaths, USS Akron in '32 with 73 deaths, and the Hindenburg in 1937 with 36 fatalities). That string of notable accidents showed that it was very very difficult for anyone with any amount of resources to operate an airship properly and avoid a catastrophic accident.

Additionally, even by the end of WWI airships had become obsolete as weapons of war. You can read more details in my previous answer here. Just as with other aspects zeppelins started out with some initial major advantages. They could carry huge quantities of bombs across long distances, they could mount extensive anti-aircraft defenses (multiple individually manned machine guns, far more than even the B17 "flying fortress" had), they could fly higher than airplanes could reach, and they were actually somewhat robust to damage (a single bullet puncturing a gas envelope just induces a slow leak). But very rapidly these advantages were mitigated. Incendiary and explosive bullets meant that any hit on an airship could easily bring the whole thing down in a flaming wreck, and they were big targets. Planes got faster and could fly higher. And techniques for attacking airships were vastly improved. Given the costs of building and crewing airships it became untenable to operate them.

During the 1930s especially airplanes got so much more capable while airships kept falling out of the sky. By then the airplane was fully integrated into every part of the industrialized military. They were used for artillery spotting, they were used for transportation, they were used for tactical ground support, they were used for interdiction, they were used for force protection at sea, they were used for strategic bombardment, etc, etc, etc. In comparison the airship could barely keep up, it had a much narrower role that was only getting smaller (in response to the greater capabilities of aircraft and anti-aircraft systems) but the costs were still huge.

I can't imagine a factor that realistically would have made airships relevant on the battlefield post WWI. They had been used in support roles (for submarine spotting around convoys, for example) but never came near their apex of relevance they had during WWI. They were too slow, too expensive, and too vulnerable (to attack and to weather).

One aspect which I came across was that the US declared helium a strategic asset and would not sell it to the Germans for their trans Atlantic passenger service so the Germans had to keep using the flammable hydrogen.
This lead to the Hindenburg and possibly other accidents.