Introduction and RPN calculator advice

[NicolaB]

I understand the evolution tree, when the chips available were really minimal. And i understand the different physical keyboard layouts to adapt to users who are accustomed to a particular model. That's fine. What i really don't understand is why you can't put a sub- or sub-sub- menu somewhere to provide what couldn't fit in the chip in 1980. For example, an upgradeable equation/constants/units library; matrix operations, and so on in every calculator.