Whatever the reason, I currently have four Macs with shot optical drives. It may well be a side-effect of kids - one of which was the subject of one of my first GeekDad posts, way back in May 2007 (in that case, it was paper shoved in an iMac's DVD slot).
That may have something to do with the amount of pet fur flying around here or the frequent renovations that have been known to kick up dust. In my experience, the optical drive is often the first thing to fail on Macs, at least around my house. With the latest round of super thin iMacs it introduced last year, Apple did away with optical drives in its all-in-one desktop PCs.
