The problem: Is Retail Media Finally Becoming an Open Ecosystem? 

‍In “the exodus”, we looked at how retailers are moving away from legacy ad serving infrastructure, and why that shift is accelerating. Part two explored why most retail media programs stall before they reach meaningful scale. The through-line between both pieces is the same problem showing up in different forms: closed systems that were never built to grow. 

This piece is about what an open one actually looks like.

From Closed Networks to Open Markets

Retail media has grown rapidly over the past few years, but it has also become increasingly fragmented.

Most retailers built their own technology stack, managed their own inventory, cultivated their own advertiser relationships, and defined their own rules. Early on, that level of control made sense. It allowed retailers to launch quickly and protect the customer experience.

As networks mature, however, that same control can become a limitation. Retail media exists to maximize the value of every advertising opportunity, yet closed systems often prevent enough demand from competing to reveal that value.

That's why the model is beginning to change. More retailers are asking whether openness and control are actually in conflict—or whether limiting access has simply been leaving revenue on the table.

The Core Shift: From Control to Competition

At its simplest, this shift isn’t about technology, but about competition.

Closed systems prioritize control, limiting access to demand. Open systems prioritize demand， creating competition around id. And revenue doesn’t come from control. It comes from competition.

The more qualified buyers compete for the same opportunity, the more accurately that opportunity is valued.

The Closed System Problem: Control at a Cost

Most retail media networks today operate as closed environments. The retailer controls access to their ad inventory, limits which demand partners can bid, and sets the terms.

That means:

• A limited set of demand sources, often just direct brand budgets
• Managed campaigns or restricted buying access
• Little to no real-time competition across buyers

On the surface, this feels safe. Retailers maintain control over pricing, relationships, and user experience. But deep down, it's a ceiling disguised as a strategy.

When demand is limited, pricing power is limited. If only a handful of buyers are competing for an impression, you’re not discovering its true value, but settling for the best offer within a constrained pool.

In that sense, closed systems don't just restrict access. They restrict revenue potential.

Open Systems: Letting Demand In

An open ecosystem flips the model.

Rather than tightly controlling who can buy, it expands access to demand through additional advertisers, buying channels, and real-time competition. That doesn't mean sacrificing quality or creating chaos. It means creating a marketplace where more buyers can compete fairly for every opportunity.

When more demand enters the auction, pricing becomes more efficient and revenue grows, not because prices are artificially increased, but because they're discovered through genuine competition.

Open vs. Closed Demand

The difference between open and closed systems isn't philosophical. It shows up in measurable business outcomes: yield, fill rates, and ultimately revenue.

Closed demand is predefined and finite. It typically relies on a relatively small pool of buyers and often requires manual management. Open demand is dynamic. New buyers can enter continuously, compete in real time, and increase competitive pressure as the ecosystem grows.

Closed demand eventually plateaus because the number of participants rarely changes. Open demand compounds because competition can continually expand over time.

Why Unified Auctions Matter

Opening up demand is only half the story.

The mechanism that makes this work is the unified auction: a single, transparent process where all eligible demand competes simultaneously, rather than being prioritized by relationship, sequence, or deal structure.

Without a unified auction, even an "open" system often falls back to waterfall logic. Buyers are evaluated sequentially, based on existing relationships or deal structures, and each additional step reduces the likelihood of finding the highest-value bid.

A unified auction removes that bias. Every impression is priced through competition, and the winning advertiser is simply the one who values that opportunity most at that moment, for that shopper and in that context.

Without unified auctions, openness is largely cosmetic. With them, competition becomes real and measurable.

The Shift That's Happening

Retailers are starting to realize that more open access to demand can strengthen monetization, not threaten it. The ones holding tightly to closed systems are protecting margin in the short term but capping their ceiling permanently. The ones opening up are inviting competition in, and watching their yield follow.

Across the industry, the trend is already visible: greater programmatic access, deeper integration with external demand sources, and growing pressure to demonstrate incremental revenue.

Revenue comes from competition, not control. In the end, revenue doesn’t come from who is kept out. It comes from how many buyers are let in, and how hard they have to compete.