Arguments for them being over - priced
A $100 PDA or cell phone outperforms a TI83+ (of equal price) by a huge margin (far more processing power and memory. I can get a $100 PDA with a 200 mhz processor whereas the TI83+ only has 6 mhz). They have color screens and can transfer information from and to a computer much faster than a graphing calculator (A TI83+ does not have a color screen. A color screen can be useful when graphing multiple curves on one screen for comparison). People are willing to write (and have written) free complicated CAS math software for PDA's and such and for computers and often times release it under the GPL. Some of the free CAS software (at least the ones for your computer) can do everything your TI83+ can do and more. Many of these devices come with sophisticated operating systems which demonstrates that it's not that expensive to write software for them. PDA's and cell phones often come with lithium ion batteries which have a much longer usage time than alkaline batteries and are re - chargeable. Furthermore, PDA's, GPS devices, and cell phones do all kinds of stuff that graphing calculators don't do (they have speakers, microphones, they transmit and receive signals, make and receive phone calls, they can take pictures, connect to wi-fi, many cell phones have GPS built in, etc...). No one is asking TI to make their graphing calculators have any of these features, which should make their cost far less. The $100 T - mobile Dash (with batteries. I think this is with a contract) weights a little more than half as much as a Ti83+ does. The open source community practically begs cell phone companies to make their cell phones open platform so they can write free operating systems and software for them, they would probably be happy to write GPL software for these calculators (and linux is notorious for being stable).
Ti 83+'s are more reliable than these devices (often outlasting them by years). They use little power, allowing them to use alkaline batteries which have a lower self - discharge rate enabling them to sit idle for longer periods of time. These batteries are also cheaper. Lithium Ion batteries can cost from $18.99 to $33.98 to replace, and sometimes more. I can get a pair of alkaline batteries for $1 and a Ti83+ requires 4. Also, with other calculators (besides TI) one can get a slightly better calculator, in terms of hardware, for an equal price.