Product strategy is the act of making explicit, evidence-backed choices about which critical problems to solve right now — not a prioritized list handed down from leadership, and not a synonym for roadmap, business strategy, or product vision (see roadmap-vision-strategy-taxonomy).
Most organizations' chronic "prioritization problems" are not actually prioritization problems — they are symptoms of never having built this choice-making discipline in the first place. See lack-of-focus-vs-prioritization-problem.
A real strategy states what NOT to do as much as what to do, and is judged by whether it has focus, transparency, and a bet behind it, rather than being "wishful thinking" — an assertion of belief with no data or reasoning to back it up.
"fundamentally the product strategy is about making those choices."