A traditional planning cycle assumes the world will stay still long enough for the plan to remain useful. In fast-moving markets, that assumption breaks pretty quickly.
The answer is not to stop planning. It is to be more explicit about which parts of the plan are durable and which parts are bets.
Hold the outcome tighter than the solution
A team can stay aligned on the problem, the user outcome, and the constraints even when the implementation changes. That gives people room to adapt without reopening every decision from scratch.
It also helps to separate commitments from learning. Some work should stay funded because the underlying need is clear. Other work exists to answer a question. Treating both the same makes a roadmap look more certain than it is.
The PM job shifts too. More time goes into keeping assumptions current, watching what customers and the market are actually doing, and making sure the team knows which decisions are still solid and which ones are moving.
The goal is not perfect certainty. It is a team that can keep moving without confusing an old plan for the truth.