In a way, there is no difference between a plan and a strategy. And yet they are not the same. It might help to consider them as elements in a perpetual implementation process.
From such a perspective one can say that the relationship between an idea and a strategy is the same as the relationship between a strategy and a plan. The latter is a path to the implementation of the former.
There is no guarantee that an idea, a strategy, or a plan can be implemented. But that’s why they are being imagined and written down. It’s to understand and determine the possibilities. And it is to determine a way to implement it.
Yes, once one starts to implement the plan it hits reality and almost immediately one may realize that the plan doesn’t work.
But that’s only a problem if the plan didn’t allow for any margin and assumed it would work out fine.
Almost always, the trick is to find a way to implement the strategy in small experiments allowing one to learn how to get to the big picture.
Sometimes this happens in thinking and sometimes in doing. And sometimes the process is such, that thinking and doing seem to be the same.