There's a nice profit margin on those calculators, but there's also a floor price for electronics at play because at some point, making outdated chips, LCDs, PCBs, etc. doesn't actually get cheaper. So graphing calculators will always cost $30-$100.
While they're wildly outdated, it doesn't make sense to arm kids going into standardized tests with Chat GPT, or even Wolfram Alpha.
Standardized test math is pretty simple. Either design the test so a scientific calculator is enough, or better, keep the numbers small enough that it doesn't matter and have answers as simplified expressions, e.g. 6*sqrt(2).