> Over the course of several decades, they must have been making a large integer multiple of the build cost in pure margin while not updating the product.

Yup, this is an open secret about calculators: they are basically regulatory capture nowadays, since you can buy much more powerful devices for cheaper. Software used to be an advantage, but the algorithms they use are now common knowledge.

You can also use an alternative like NumWorks, that has source-available software and lets you run your own code; they have played the regulation game and have a reset button that allows them to be used at some exams in France, Italy, Netherlands, some US states, etc.