They have become commodity items like the $2 plastic grocery store light because the consumer is known to shop only by price, so reliability has suffered.
I have found that (besides the infamous IBM 75GXP series that led to the sale of their entire drive division to Hitachi) modern drives tend not to fail outright, but dramatically fall off in performance because the firmware is so good at automatically remapping bad sectors. I've had to RMA a whole stack of Maxtors (and a few each of WDs and Seagates) because the performance dropped to <5MB/s and yet the data on most of them was still readily accessible (if slowly).
But there are high quality drives intended for servers that require reliability above all else, though they are of course ridiculously expensive. The solution is to buy used or refurbished, because a used Surefire is more reliable than any $2 flashlight
no matter how new it is. These things retain their resale value very poorly (because if absolute reliability is required then no corporate IT guy is willing to risk being fired for specifying used or reman parts) yet because they were originally built to sell for over $1,000 the quality is topnotch. As an example factory refurbished 15,000rpm U320 SCSI drives are about the same price as brand new 10,000rpm SATA WD Raptors of the same capacity, though of course you must then add in the price of the U320 controller.
I've been using such drives for the last six years and have never had one fail. In that same time dozens of my consumer grade drives have, and of those mostly in the last two years. So yes, I do believe they have been more cheaply built recently. A few years ago most of the major companies switched to 1 year warranties (from three) for their consumer drives, but just this year many have returned to the old 3-5 year warranties (though I did note that the manufacturer's drive utilities now report no errors even if performance falls way off or Event Viewer reports millions of timeouts or atapi errors from the disk).
May I suggest the
reliability database at SR (registration required)?