[JoeCortopassi]

The case is not trivial, not crazy, but not trivial. It's also the least hard part about putting together a similar package. A non-EE type person could probably get some dev boards from sparkfun/adafruit, and connect them up to a raspberry pi with some sort of display with some buttons. But that last mile of getting them to play nice, not be a massive battery hog, and have simple/usable software is man-months of work. This also assumes you have a passing knowledge of circuits and are decent enough programmer to get a job, neither of which are low bars

This is likely @pierat's point: sure, it's possible, but your diy version will be objectively worse in a variety of ways while also taking you a pretty long time to put together.

[evilduck]

I agree, the skill acquisition time and effort would keep out script kiddies and normal consumers, but there's a large number of people who do have these skills, especially on this site.