We have a client (a factory) I wrote a massive (for one person without AI) Clipper system for that runs the factory; this is decades ago but it just works and when they tried to replace it (not by us, but promises by others), it was worse and they did not switch. Cheating, but another client is a bank; they found its is really inefficient to not use DOS. Their machines use Windows but fullscreen DOS box you cannot close or minimize with the app in it.