The HP-33E/C that could have been.

[lvt]

I remember when I bought my first pocket PC in the 90 (a Psion), the 256KB version is significantly more expensive than the 128KB version, or you can buy a memory card.

Maybe consumers faced the same problem in the 70's. A calculator with larger memory (higher registers count) would cost more to produce and buyers have to pay more than what they actually need.