Why are graphing calculators so expensive?

Ok let me see
It says that :
In today's world of high-tech gadget's, Texas Instruments' relatively low -tech calculators stand out. Since the 90's, laptops have gotten faster and thinner, phones have become more powerful, and watches can pick up WIFI- but the TI-83 graphing calculator, which was launched in 1996, essentially remains frozen in time. With a 6 MHz processor, no rechargable battery, and a screen like an old Game Boy, the TI-83 is far from impressive.