Very good reading indeed.
I bought about 40 (cheap) NAS 3 years ago with Seagate drives.
They all died due to disk failures within 24 months.
I realised afterwards I was unlucky as that one specific Seagate was bad luck (bad firwmare, "busy" mode bug...).
Still, next batch I buy wont be Seagate drives....
Where I work, we also that many WD drives : these are pretty good.
As a whole it would be interesting to know what fails : the electronic part or the disc/media part.
Another interesting part would be : does failure rates change with SSD drives.
And last but not least, the conspiracy guy I am could wonder if since profesionals all make their drive redundant (x2,2,4,5,10, etc) : are not drives programmed to die after X (short) years.
Or the other me, the "old" guy could also wonder : were not drives lasting longer before? as in "it was better before"
/Erwan