You think we have LESS data now than we did in the past?
We have more than ever, and easier ways of collecting data than we have ever had.
As soon as you stick the data through an algorithm without getting permission from everyone in the dataset, you're getting put in prison for GDPR violations. Have fun getting consent from 100M people with only their postal address from 50 years ago.
(1) Public Health Exemption Legislation
(2) Use the NSA/GCHQ to get the data, run the analysis and once you know the answer do parallel construction with a much smaller, legally available dataset.