Pretty sure they did stop making the 3 actually. Still selling it, and refurbs, but no longer manufacturing. Currently being actively made are the iPad2 (for budget folks), iPad mini, and iPad 4.
Joke. Joke. JOKE!
Kinda. The new ones come out so fast word probably takes a while to head back to manufacturing so they know to erase the '3' or '4' on it with a little whiteout and write '5' on them.
ALSO A JOKE. SARCASM IS EMBEDDED IN THIS POST.