was the norm
In the US, it was only banned from being sold in 1996, but it wasn’t the norm for long before that. The last model year that leaded gas was allowed for cars was 1974. Yes, all Boomers and most of Gen X would have had high exposure, but it would have been fading out by the time younger Gen Xers were born.
And yes there are some non-car applications of it that are still legal to this day, but the overall frequency of it would have dropped a ton well before the mid-90s. (Source, and actual graphs of the decline over time)
It’s a setting that’s off by default in Voyager.