Your product does not exist in isolation
Forces outside your scope affects product metrics. And it is still your job to understand them.
When a product metric drops, we immediately look inside the product - if something changed/broke. Sometimes that is the reason. But not always.
Digital products cannot exist in isolation. The way your users engage with your product is shaped mostly by forces outside the product. For eg, a drop in stickiness may have a lot to do with your lack of social media presence. A fall in conversion may have more to do with trust, branding or poor customer support than with the product flow.
Social proof, familiarity, herd behaviour - all these matter. What your users hear about your product matters.
This is why product metrics can be misleading if viewed too narrowly. A product manager has to look beyond the dashboard and ask what else might be influencing behaviour.
And you rarely find that from data alone.
Conversations with users often reveal the real reasons. What made them trust you, what made them hesitate, what made them return, or why they quietly left.
Some of those questions may sit outside your immediate scope. They may belong to marketing, support or branding. But they still affect your product. And that still makes them your problem to understand.