Right, the TI-68k series are really expensive now if they're bought brand-new. TI lowered the price of Nspires, raised the price of TI-68k calcs, and distributors raised the prices to insane levels...

Are the 68k really so much better programmable?

Sure, there's really no doubt about that
* BASIC programming is more advanced: it can output to the screen, it can read the keyboard, it can launch ASM programs and FlashApps.
* C/ASM programming is more advanced. People don't have to fight against a huge OS, which provides no support for programming. They don't have to spend time finding holes in them so that they can exercise their fundamental right to do whatever they want on the devices they own.
People can just use the official way to get access to 1500+ functions and variables, 1000+ of which are well documented, either officially (TIFS) or unofficially (GCC4TI). Instead of having to fight, they can (and do !) just build functionality - mostly games, but also native code math programs - on top of that foundation.
* there are various minority languages, such as a version of GFA-BASIC, NewProg (which predate Axe and Grammer for 83+-class calculators, BTW)... There is even an implementation of Lua, which never got the success it could have deserved. Needless to say, it's significantly more standard than TI's proprietary Lua for Nspires is - for instance, it can read and write files.

Seriously... four years and a half after its introduction, the Nspire series has unbelievably few programs !
At the end of the 1990s and the beginning of the 2000s, programmability was an integral part of the success of TI's calculators in the marketplace. Nowadays, TI listens to teachers and test regulations - making their machines less powerful, less versatile, and less desirable in the process.

TI doesn't need to make programming easy, teachers will tell their students to buy a calc anyway

Yep.

and a "better" screen (non-cx)

Indeed, the "better" is only on the higher resolution. The slowness of the screen was increased even further... The screens of TI-Z80 and TI-68k calcs aren't that good, and the screens of Clickpad and Touchpad Nspires are much worse.
Fortunately, TI fixed their wrong ways on the CX series.

It's been a while since last I've been here and I know it's frowned upon in many forums to bring back something that's been dead like this but all I'm here for is an update.  Has anything happened in the last few months?  If not, I'm going to lock this thread next week.