the places where I drink them appear to go through a pretty high volume
In Laos?
Here in Thailand one single importer takes old stock form Laos, then it sits around in blazingly hot warehouses and trucks where it cooks. There is no correlation between here turnover, volume and freshness, when it comes to Beer Lao, as it comes into Thailand already months old.
In Laos, especially in cans, it can be pretty good, if fresh.