What if the interviewer asked a different question - Why do we need a PM, we have already built-in the solution and our users are happy to use it. Convince me to hire a PM.
Explore the genesis of the question. Understand what they feel the PM role is all about. And then explain that it isn't about building it once as competition would keep coming and you would need to improve the product + launch new use-cases regularly to compete with them.
What if the interviewer asked a different question - Why do we need a PM, we have already built-in the solution and our users are happy to use it. Convince me to hire a PM.
Explore the genesis of the question. Understand what they feel the PM role is all about. And then explain that it isn't about building it once as competition would keep coming and you would need to improve the product + launch new use-cases regularly to compete with them.