One of these days I was at a small grocery store in my hometown, and saw the screen of a POS system I had built in the late 90s with Visual C++ 6 running on Windows 10. The guy told me he got the system from the previous store owner he bought the shop from, it did most of he wanted it to do, and that his son is the guy who do things like upgrading the hardware, and writing small python programs that talk to the same SQLServer database to extend the system and implement some integration, so he sees no reason to get another system.