Don't fix what isn't broken: https://www.tomshardware.com/desktops/indiana-bakery-still-using-commodore-64s-originally-released-in-1982-as-point-of-sale-terminals

In my professional opinion this is the best malware protected setup I have seen for years.

Indiana bakery still using Commodore 64s originally released in 1982 as cash registers — Hilligoss Bakery in Brownsburg sticks to the BASICs

If it ain't broke...

Tom's Hardware
@masek c64’s rather famously have components die from time to time. I wonder where they get the spare parts?
@seeteegee @masek Caps will need replacing, at least, but those are standard components.
@mlepage @masek I hear that entire IC’s die on them, some are getting scarce.