Gibson Biddle frames Product Strategy around Hamilton Helmer's definition: strategy is 'a route to continuing power in a significant market.' Biddle illustrates it with the historical Silk Road — a durable, defensible trade route that generated sustained advantage for whoever controlled it, rather than a one-time win. The framing emphasizes durability and defensibility over a single clever move: a real strategy compounds power over time in a market worth controlling, which is the same durability test DHM Framework (Delight, Hard-to-Copy, Margin-Enhancing)'s 'hard-to-copy' axis is trying to operationalize at the idea level.