No one can be a bystander on product strategy. Just because you've got product in your title doesn't mean you're the only one that should be thinking about product strategy.
Strategic alignment requires cross-functional leadership
Leadership → Stakeholder Management
You're actually a company exec first and a product exec second. You have to not only truly care, but create the perception that you care about sales, about marketing, about legal, et cetera.
The big growth levers are strategy problems, not individual departmental problems.
What we see in Shape Up teams when they hit their stride is that the PM moves upstream. So the PM is less busy with, 'How do I get this project to not be in a bad state when it's getting built?' And they're way more in, 'How do I understand the business context? How do I narrow down the problem? How do I negotiate back and forth with maybe the CPO who brought this to me to understand where the core of it is?'
What typically happens is product's working on some stuff, sales is working on some stuff, marketing's working on some stuff. Marketing in their own little bubble comes up with positioning, they might build some stuff for the sales team, heave it over to the sales team. Sales team looks at it and says, 'I don't get what any of this stuff is. I disagree with this. This doesn't match what I see,' and they just throw it out.