Unless one lived through that time I doubt they would be able to accurately describe the general emotions of the population. To those of us who value historical data one could say that the general feeling in the USA by 1938 was one of conservative optimism. The worst part of the Great Depression was almost over, jobs were once again available and the various government policies had addressed, with some success, the worst of the economic problems. FDR began his fireside chats in 1933 and they continued almost until his death giving much positive spin to the nations issues. While there was much anxiety over the "international" situation there was also a national opinion that the USA was relatively safe behind its two oceans and a president whose public policy was to "keep the boys out of another European conflict". The years from 1938-1940 would prove that optimism was unwarranted but in 1938 the terrible war ahead was not anticipated by many.
And, I still ask, how the Earth-bound situation was a significant factor in the panic following the WotW broadcast? There is virtually nothing I have found in my history searches to indicate that the general population of the United States was overly concerned with Martians or any other space aliens. There were, of course, comic books and radio shows that touched on space travel and other celestial events but it doesn't appear to me that these were significant enough to instill fear or even concern in the average adult of the day. And as popular as radio was in 1938 I am absolutely sure that most adults along the East Coast realized that the source of the hysterics were coming from the well known Mercury Theater of the Air and not a verifiable news outlet.
This topic seems to have run its course so I will conclude in agreement with my initial statement - that people who believed an obvious radio entertainment program were either susceptible to flights of fancy or terribly uninformed, possibly both. And given the current climate of our country I am relatively sure it could easily happen again.