> people go into business with this as a strategy
Very very few truly do as you state at face value. Most people go in with a plan and rarely want to hard pivot.
But, starting a business is a test and the outcomes of the test shows whether it's working for you or not. Many times its fundamental business problems (homejoy) other times it's you (friendster vs fb).
There's no right/wrong way to decide what is the correct move because whatever example someone provides, there's plenty of counter examples.
But, firing as many bullets as possible helps reveal what potentially works and to double down on. Sometimes what is showing signs of life is an aspect of the business that's not directly related to your current core, but pivoting there means survival. That is the hard pivot (segment.io).