Those are big factors.

Here is a potentially more minor one. I think Americans are tired of being fearmongered by the government for the past 20 years especially, but even the past 70 since WWII. One "crisis" after another. We learned to distrust. And this is why in places where life was pretty damned good and calm, like Australia and NZ, they fell for this new "crisis" hook, line, and sinker.

At the end of the day, THE END IS NIGH! REPENT NOW!, just takes on different forms. And people get tired of it.