Discounting is not spread evenly through the year. It concentrates into a small number of periods that most retailers observe simultaneously, and the clustering is deliberate.

Shared events expand the audience

A promotion run alone reaches only the retailer's own customers. An event observed across a whole sector puts the category into general attention.

That attention brings shoppers who were not planning to buy anything, which expands the pool every participant is competing for.

The expansion is usually large enough that a share of a bigger audience beats sole access to a smaller one, which is what sustains participation.

Non-participation is expensive

Once an event is established, a retailer that sits it out loses sales during the period without gaining anything at full price afterwards.

Shoppers who intended to buy simply buy elsewhere, and the absent retailer also forgoes the traffic the event generated.

This makes participation close to compulsory regardless of whether the individual economics are attractive, which is why events persist after they stop paying.

The calendar follows demand, not the reverse

Events sit where demand already existed: seasonal transitions, holiday preparation periods, and the points at which households have money to spend.

Placing a discount period where demand is already high looks inefficient, but the alternative of promoting into a quiet period generates little response at any depth.

Retailers therefore compete for share during the peaks rather than attempting to create demand in the troughs.

Events invented outside existing peaks generally fail or fade, because a discount alone rarely persuades a household to buy in a period when it had no intention of doing so.

Supply chains are built around the peaks

Concentrated demand requires stock positioned in advance, additional warehouse capacity, and temporary staffing, all committed months earlier.

These commitments are made against forecasts, and a misjudgement produces either lost sales or residual stock that must be cleared afterwards.

The cost of that capacity is a structural argument against clustering, and it is why some retailers try to extend events over longer windows to flatten the peak.

Extension dilutes what made events work

Stretching an event across weeks reduces operational strain but weakens the deadline that produced the concentrated response.

As events lengthen, shoppers stop treating them as time-bound, and the promotional period gradually becomes an ordinary trading period at lower prices.

The pattern repeats across the calendar: an event forms, expands, loses its urgency, and a new concentrated moment emerges somewhere else.