$80M is nothing for a clinical study. I’ve seen $100M thrown at device development with no new hardware and only new software to massage and display the data in new ways.
The cost/benefit is definitely there, so either the kill was requested for other reasons or the researchers aren’t telling the full story.
Of course the CDC could conduct the study on their own, but then Pfizer wouldn’t get all the benefits. Another incentive for them to do this...More to this story I think.