I wouldn't say the war impacted the parental decision(s), historically kids always played outside so they were just continuing what they knew, but we kids did have safety in numbers and that's why I'd say this is a perpetuating issue.
If a parent today told their kid to go outside and play, that kid would be alone and less safe. So parents just don't allow it.
Speaking of rolling, that's what bikes were for. Running around unsupervised in the neighborhood. I'm not sure what kids do with bikes today. Or if they even get bikes.
My parents live in a subdivision with several parks that are completely empty. I took my niece to one and discovered that's apparently suspicious behavior to use a public park in the middle of a weekend afternoon after a local PD officer stopped by to "have a chat."
The police also literally barricade the subdivision for Halloween. Nobody comes in or out between the hours of 7 & 9.