The short version
Product strategy is the argument for why your product will win: which customers, which problem, and why you beat the alternatives. It is not the roadmap; it is the reasoning that decides what deserves to be on the roadmap at all.
What it actually is
A real strategy makes three claims: this user has this problem, existing options fail them for this reason, and we win because of this advantage. Everything else, features, pricing, positioning, should trace back to those claims or be cut.
Why teams argue about it
Most product conflict is strategy conflict in disguise. When people fight about a feature, they usually disagree about who the customer is or what winning means. Writing the strategy down turns those hidden disagreements into decisions.
How to think about it
Strategy is choosing what not to do. A useful test: if your strategy would also be true for your competitor, it is not a strategy, it is a goal. Good ones are falsifiable, name their trade-offs, and fit on a page.
