Steve, all over the world -- car plants, power plants, steal mills, candy factory, tire plants, Caterpillar, John Dear and any other place that incorporates chain drives has chain stretch. The term on the maintenance technicians work assignment notice is generally " chain stretch on xxxx- replace same with xxxx"

Must be only on chain saws they don't stretch.

Call it what you wish, the bugger is just plain worn out, if you cannot adjust it any more.