It is only given for bravery in face of the enemy, so the fact that combat was far more mechanized in WWII ( ie fought at long distances from the enemy) is often offered up as the excuse.
Dropping bombs from 20,000 ft might seem then to eliminate you from ever receiving a VC in theory --- but not in practise.
Bomber crews actually did get VCs ---- for trying to save fellow crew members high up in the flak-filled skies.
The other view - mine anyway - is that people were less selflessly brave, over all, in WWII than in the earlier war.
The character of virtually all the world's western-influenced population changed - for the worse - after WWI .
But not as a result of WWI , merely as the result of death carrying off the holders of older Victorian views on selflessness, replaced by the young bearers of the up-to-date, modernist , scientific, view of the proper morality:
"Be quick to defend your own national group to the death (and beyond) - but ignore or despise all others' cries for help."
In the 1930s and early 1940s, Philip Marlowe's mean streets were world wide......