Release dates for large games are not chosen freely. They are the outcome of a scheduling problem involving competitors, retail cycles and a small number of genuinely valuable weeks.
Attention is the resource being competed for
A major release needs coverage, creator attention and the audience's discretionary time, all of which are finite in any given week.
Two large games launching together split every one of those, and the smaller of the two typically absorbs most of the damage.
Buyers also have limited money and limited hours, so a purchase made in one week is frequently a purchase not made in the same week for something else.
Only part of the year is genuinely attractive
Late autumn concentrates gift-driven purchasing, which makes it the most valuable period and also the most crowded one.
Early in the year is quieter and offers visibility, but sales volume is lower, so it suits mid-sized releases better than the largest ones.
Summer is traditionally avoided because engagement falls, though that assumption has weakened as gaming has become less seasonal.
Publishers signal rather than negotiate
Direct coordination between competitors would be legally problematic, so scheduling is conducted through public announcements and inference.
Announcing a broad window rather than a date is a way of claiming territory while retaining the ability to move, and rivals read those announcements carefully.
The first publisher to commit to a specific date effectively forces others to work around it, which is why early date announcements carry strategic value beyond marketing.
Genre proximity matters more than size
Two large games in different genres can coexist, since their audiences overlap only partly and their coverage draws different attention.
Two competitive shooters, or two long role-playing games, compete for the same limited hours as well as the same money, and that competition continues for months.
Live service titles complicate this further, because they compete for time indefinitely rather than at launch, and a strong incumbent can suppress a newcomer regardless of quality.
Late movement is expensive but common
Windows shift when a competitor announces something unexpected, when a delay elsewhere opens space, or when a publisher decides an occupied week is now survivable.
Moving late means rebuilding a marketing plan against a new context, which costs more than choosing correctly at the outset.
Publishers accept it because launching into the wrong week costs considerably more, and the difference between a good window and a bad one persists long after release.