I think one factor that influences a person's level of cautiousness is the region of the country someone lives.
In full disclosure, I didn't take the threat that COVID-19 seriously at first. But when the number of diagnoses (and deaths) piled up here in LA, my cavalierness turned into caution. It took living within a community that was definitively impacted by the fallout of the disease to change my mind.
My sense is that most regions of the country have not hit their peak or that their communities are spread out over a large geographic area. In either case, the likelihood of them coming in direct contact with someone who may be a carrier is lower than it is in a major, dense city. Direct experience is a greater 'teacher' than observation in most cases.
As the virus builds towards a peak and more communities are deeply affected, hopefully more people take this outbreak with the proper level of gravity. At least before conditions worsen.