Do note that rapid decline in the day-to-day increase of case numbers is not necessarily indicative of rapid decline in transmission rate. Transmission rate could have declined gradually over the course of a week or more, and the rapid decline in day-to-day increase of case numbers could have just been detection catching up with existing infections.

Their daily testing was reasonably consistent over that time period. So, their is some wiggle room, but it’s at minimum a 80% drop over 2 weeks. Compared to the US where daily numbers are steady for weeks with the last two days having the greatest number of detected cases.

I've given up on the USA numbers. There is no way an underlying exponential process is going to deliver you a near constant 30K new infections for nearly 4 straight weeks.

Something else is driving those numbers, and it ain't the actual number of new infections. For me the obvious candidate is they hits some testing limit.

You shouldn't think of it as one underlying exponential process though. It could be many overlapping and time-delayed S-curve type graphs which are additively causing a constant rate of infections.

Although it's also most certainly true that we're vastly undercounting the cases in most (if not all) areas.