Mac Pro DVD drives are easily replaced

Since purchase, the single DVD drive in my Mac Pro has been, well, broken. After disc insertion, it almost always makes a horrible grinding noise—not the loud spin-up-style noise, but a low, rumbling noise that sounds quite literally like it's going to shake itself off its mount. I'm fairly sure it's been reported elsewhere. It's taken me over a year to do anything about it, due to a combination of factors:

• I actually use the drive pretty rarely. Almost all software I buy these days is downloaded. DVDs as storage media are going the way of the CD: 4GB isn't the vast expanse of space it used to be, and, frankly, optical media are pretty fragile. (And the failure modes of DVDs seem to be catastrophic: what's with a couple of scratches making an entire disc unreadable?) At $A 176 for a 1TB USB disk, I can't see myself buying too many stacks of blank DVDs in the future.
• It usually works. Often, it will spin the disc up, growl once or twice, then settle down. Other times, it won't read known-good discs at all. And very occasionally, I am pretty sure it has damaged some discs.
• Despite having purchased the 3 year Apple Care option, presumably entitling me to a free replacement for the faulty drive, powering down the Mac Pro and sending it into a store (for what would presumably be a minimum of a week) would cost me more in time and energy than replacing the drive myself, at my own expense.

I had a spare LG DVD writer just lying around, so I grabbed a screwdriver, and a copy of the Mac Pro User Manual, and set off. It's about a 10 minute job, almost completely described by the manual—you do need to prise the faceplate off the front of the drawer if it's a drive intended for a PC-style case. (Otherwise the front of the drawer won't physically fit through the auto-opening slot door on the Mac Pro's case.) If you're into this kind of thing (industrial design, and computer design in particular), the internals of the Mac Pro are spectacular. Why can't other companies design cases like this?