There are two things I’m thinking about. First, implementing ideas into policy on a large scale. An example could be the idea of communism, a big argument is that communism seems ideal on paper but not in practice.
Second, implementing ideas into a routine or protocol. An example of the former could be a conflict between time management and reality such as trying to designate a certain amount of time to complete a set of tasks. Sometimes things take longer than expected and all the planners and schedules in the world can’t fix that. An example of the latter would be employees being told to always wash their hands when they get dirty but if it is busy, sometimes it’s just not possible to do that every time.
I know these are a lot of different things and I don’t expect a word that encompasses all of them. Anything even remotely related would be appreciated.
Best Answer
A contribution to the spectrum of meaning that you refer to is Pipe dream.
That brings to mind pie in the sky, castles in the sky, fool’s paradise, or even a chimera.