Advice for a PM working inside a Vision Vacuum: No Vision, Not Bad Vision, Is the Real Failure Mode: don't panic; form your own point of view on what the vision should be; lean on research teams for validation; read Inspired and Empowered; start introducing ideas to your manager; and begin informally educating the company on what a real vision looks like and why it matters. The aim isn't to single-handedly write the company's vision, but to build the case and muscle for one until leadership adopts it.
When leadership hasn't articulated a crisp company-level strategy, PMs often use that gap as an excuse to skip Product Strategy altogether — but even a fully crisp company strategy would only ever supply minor directional guidance, so its absence is a smaller obstacle than it's treated as. A two-step substitute:
Even with a clear company strategy in hand, the genuinely hard, undelegable part of product strategy is unchanged: insights and creativity about your specific product, target segments, and competitive differentiation (see Four Sources of Insight (for Product Strategy)). Company-level strategy cannot substitute for that work — its absence is an information-gathering gap, not a blocking dependency. See also Product Strategy Excuses as Fear-Avoidance for why PMs reach for this excuse in the first place.