In this context that would mean running the same intervention at scale 30 times without each run impacting the next. Maybe that is possible, but it seems unlikely to me especially if the intervention has a half life on the order of a single generation as life experience and social norms change.

The initial run is usually a relatively small scale. What works in NYC may not work in LA but it’s likely to work in many locations.

The question I was raising was locality though, it was temporal. Such experiments take time to conduct, and running a couple dozen or more times takes even more time.

The question I was raising was whether said results would be useful beyond a decade or two into the future, not across different cities today.