I think it stems back to the taiwan floods which happened when 1-1.5 TB hard drives were the big sellers. Remember, there was flooding that killed the hard drive market for like a year, and companies (particularly seagate) had to scramble for alternative, perhaps slightly grayer, sources for their stuff. That was precisely when I started noticing dramatic increases in the number of seagates that were failing on me, compared to western digitals. However, since then, the manufacturing/supply has recovered for the most part and I think we're seeing a return to normalcy.