It doesn’t mean we shouldn’t have one in the first place.
In today’s world of rapid deployments and “the plan is no plan”1, having a plan written down not so cool as not having one. Why would you bother, when you know for a fact that it won’t go as you planned anyway? It’s an exciting notion to just jump in without any preparation whatsoever like the swashbuckling adventurers of yore.
But I beg to differ.
As the saying goes, no battle was ever won according to plan, but no battle was ever won without one.2
Don’t ditch the plan altogether. It is still a useful tool. It clarifies goals, visions, methods, and foresees future issues. Just don’t expect it to be right on the money. Predicting the future (basically what plans do) is a very slippery business. No one will get it right every single time. Heck, no one even gets it right most of the time. Just ask the financial traders. Or an economist.
I’d say have a plan, yet still be ready to adapt.
1 It’s even the title of a movie.
2 Attributed to Dwight D. Eisenhower.