I think the problem should be solved within the OS using sandboxing, like in iOS (or to some degree Android too) and macOS and Windows store applications. For e

I think the problem should be solved within the OS using sandboxing, like in iOS (or to some degree Android too) and macOS and Windows store applications. For example, when you uninstall an app, there are no leftovers in the system. You don't need to check, if file exists or not ... To some degree, this has been also solved with containers. It's much easier to create new container image, then create proper idempotent script. And you can create create image from running system too. So you can just "bash" commands and don't care about the state of the system. When done, you just create final image and you can be sure, that state of the system in the container would same as you intended. I'm talking mostly about install scripts. Of course there are valid use cases for idempotent bash scripts.