The common theory of monopoly death: a better competitor enters, takes market share, the monopoly declines. This happens, but it's not how most monopolies actually end. Most monopolies die from irrelevance — the thing they control becomes less important, and the monopoly position becomes worthless.
A monopoly is valuable only if the market it controls is valuable. When the market shrinks or disappears — because of a new technology, a shift in what people need, or a structural change in how the problem gets solved — the monopoly disappears with it.
The newspaper industry is the clearest recent example. Classified advertising was enormously valuable, and for decades newspapers had a monopoly on it in their local markets. Craigslist didn't take their market share in classified ads; it made classified ads nearly free, destroying the market rather than competing for it. The monopoly died not because someone competed better on the old terms, but because the old terms ceased to apply.
This pattern repeats across industries. Film photography didn't lose to better film — it lost to a world where film was irrelevant. Travel agents didn't lose to better travel agents — they lost to a world where most travel bookings don't require agents.
The implication for strategy: monopolists are more vulnerable to market redefinition than to direct competition. They can see direct competition coming and respond — they have resources, relationships, and structural advantages that make catching up to competitors expensive.
Market redefinition is harder to defend against because it's harder to see, and because the defense often requires cannibalizing the existing monopoly. A newspaper that builds a free digital classifieds platform is destroying its own most profitable business line. The math doesn't work until it's too late to matter.
Monopolies tend to look invincible until they don't. The transitions are often faster than the lead-up suggests — many years of slow relative decline followed by a sharp collapse once the irrelevance threshold is crossed. This makes monopolies dangerous to compete against directly (they're still strong) and dangerous to join (the decline may be closer than it looks).
The useful question about any powerful incumbent isn't "how do we compete?" but "what would make this whole market smaller or less important, and how close is that?"