I don’t disagree with anything you have said. I don’t know if it was meant as a refutation of something I had said or not. Yes, given the size of the United States, and the timing of the arrival of the virus, we have essentially had a bunch of wave patterns adding together to form the counters of the national daily death reports. I think the curves are a bit more synchronous now.
The variation between the regions of the United States contributes to the difficulty in knowing the national infection fatality rate. The population and the environmental conditions will likely affect infection fatality rate. In addition, as you probably know, infection fatality rates tend to fall over the course of an epidemic, however, As weather worsens, people cluster closer, and initial virus exposure is larger, we may experience a bump in ifr before a late winter/ earlyspring decline.
Btw, Santa Clara was cooler than NY during their peak. When Ionnaidis I came out with his prevalence report, and subsequent IFR estimate, which greatly differed from the NY data, I checked.