Yep! In some countries, TI have lobbied their way into the school system in order to make their products mandatory for tests and exams. They are then free to charge the same amount of money for a 27 year old design
It's silly, but I think that this is just because any calculator that is more useful would also make cheating too easy and would also provide too much assistance. Teachers know what the TI-84 can and can't do, so they don't have to familiarize themselves with the risks of any new model. The price is ridiculous though, I'm quite sure that Texas Instruments makes a mighty profit on these things.
I loved the TI-84 when I was in highschool. Instead of doing whatever I was supposed to do, I was programming silly things on the calculator. It had quite some programming functionality, and I constantly kept finding new and interesting things to do with it. It played a part in me studying computer science, which the teachers recommended me to do because I was constantly programming on the calculator. I still have it, though I currently don't have any batteries for it.