I think the only reason the iPad 4 was released this past fall was because of the new connector. For people who buy iPhone 5 and iPad--they aren't going to be happy about having 2 different connectors. So they had to put an update out so that everything has the same connector.
I'm hoping for a March release of iPad mini with retina display. I'll buy one even if the price stays the same, but I'd probably still keep my iPad 3. No compelling reason to upgrade it, and I'm stuck with the old connector on my iPhone 4s anyway.
Once Marvin App gets auto-scroll I am going to want to kick my Nexus 7 to the curb, but I REALLY would prefer a better screen on the iPad mini before I do that.
And if Apple does go to a 6 month release cycle... it doesn't bother me a bit. The stuff holds its value very well, and it gives you more opportunities to upgrade, if you choose to. I don't mind trading up if I can get back 70% of my investment on the older model. How many tech items can you say that about?