Looks like Apple is trying to clean their inventory's as they are wiped out of just about every model in their Refurbished units?
I personally wish people would clean out their apostrophe-s at the end of almost every word that happens to end with an 's'.
That personal peeve aside, I was quite surprised when there were no laptops available at all the other day, but after doing a quick search on the site (handy tool that), some of the explanations made perfect sense.
There's most likely simply a situation such as my own - I waited for the new models to come out, then pounced on a refurb from the previous model. The refurb price dropped and I saved some coin. As I wrote in another post, it appears I got the last available refurb of my specific model, as I've not seen another of its ilk listed for almost 2 weeks.
If you see one you want, pounce.