Platform Decay is the definitive economic lifecycle of two-sided digital monopolies, and it explains why the internet feels increasingly hostile, expensive, and cluttered.

To understand why this happens, you must look at how platform incentives shift across three distinct phases.

In Phase 1, the goal is to acquire a massive user base. The platform uses venture capital to subsidize the experience, offering low prices, no ads, and superior functionality. This generates massive consumer surplus. Think of the early days of Amazon, when the search algorithm prioritized the cheapest, best-reviewed product, or Uber, when fares were consistently lower than traditional taxis.

In Phase 2, the platform pivots to baiting suppliers—merchants, creators, or drivers. Because the platform has successfully locked in a massive audience, suppliers have no choice but to join. The platform’s network effects become so powerful that it acts as a gatekeeper.

In Phase 3, the decay sets in. Once the platform is an essential utility, it begins to aggressively extract economic rents. It no longer needs to compete on quality, because the switching costs for both users and suppliers are prohibitively high. The algorithm stops prioritizing what the consumer wants and starts prioritizing whoever pays the platform the most.

We see this clearly in the UK today. Amazon’s search results are now dominated by "Sponsored" products rather than the best options, with Amazon’s take rate from sellers ballooning to over 45%. Meanwhile, food delivery apps like Deliveroo and Uber Eats have entered a cycle of decay where menu prices are inflated, and service fees are layered on, extracting value from both the independent restaurant and the hungry consumer.

For A-Level students evaluating market failure, platform decay is the ultimate example of why competition policy is so difficult. Traditional regulators focus on whether prices are rising for consumers. But in a decaying platform, the harm is more insidious: it is the degradation of the product itself and the "tollbooth" fees extracted from businesses, which eventually force prices up across the entire economy. As long as users feel trapped by the network, the platform has zero incentive to stop the decay.