It’s a common elemental theme we see across stories, fantasies, etc. It seems like it is an element that should be part of that pantheon but maybe there is a scientific explanation of why it isn’t? Or is it simply, they did not have enough understanding of it at the time those 4 were suggested.
In antiquity people probably considered it a form of fire since anything struck by lightening tends to burn or at least get extremely hot? Or possibly they saw it as some combination of wind and fire maybe?