It looks to me like this analysis is ignore the age of drives. Specifically it might be comparing the current failure rate of years old drives against the failu

It looks to me like this analysis is ignore the age of drives. Specifically it might be comparing the current failure rate of years old drives against the failure rate of months old drives. This is likely to make newer disks look much better. I'd love to see some attempts at calculating mean time to failure (which is admittedly difficult to estimate until you have had a disk long enough to see a whole generation of them fail).