I have never understood whether and how live programming could be applied to programming a live-action game or an application that monitors and controls a manufacturing process. Is live programming only applicable to a well-defined subset of applications?

I think it's a potentially large piece of (as Alan Kay puts it) the software revolution that "hasn't happened yet". There's a lot of power there, but it's not really been explored yet, because it's not the familiar concept for how such things work.

@Dan Swirsky this has been done https://github.com/arcadia-unity/Arcadia

Thanks. I'll take a look