nowhere have I seen, heard, or read a plausible reason... there was never any sort of panic like that

I prefer concern instead of panic. There hasn't been serious widespread concern in the US like this since 1918. Not even polio or aids.

We are blessed that this is exceptional.
Sadly, the blessing is also a curse because it makes us complacent.

Given no vaccine, the best plan for handling a disease is to keep the case count low enough so that the public health folks handle it with case tracing and the public not much noticing.

Since 1918, the US has mostly managed to do this. The epidemics you mention did overwhelm public health folks and cause widespread concern, just not here. Without that lesson, the US social norms are not ready to get in front of the problem. In China, Sars got them ready, so they were able to get back ahead in a month or so.