They may have more recent data (they almost certainly do), but are not publishing it yet.
They might say that it needs to be verified and analyzed first - but they may be dragging their heels because of the implications of what they are seeing.
As you point out, it is likely that many more people have been exposed since the beginning of May - and death rates are dropping.
Yeah, a two-month old survey is ridiculous.
Haven’t seen any useful reporting of antibody testing results lately.
The CDC documents COVID-19 Serology Surveillance strategy, types, and data at:
https://www.cdc.gov/coronavirus/2019-ncov/covid-data/serology.html
The current summary from CDC as of June25, 2020 is at this link:
https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/commercial-lab-surveys.html
Note that all six surveys reported ended long before the peak infection period of this pandemic (last were Utah and Connecticut ended May 3).
The only current Serology Surveillance surveys not reported here are San Francisco and South Florida, neither of which would be of much relevance to the USA as a whole.
So I submit that they do NOT have any current data, and in fact are not even looking. That seems completely unacceptable to me!