A delay is usually described as more time to finish the game. The direct cost of that time is real, and it is often the smallest part of what a postponement actually consumes.
The team is paid regardless of what it produces
A large production employs hundreds of people, and extending the schedule means paying all of them for the additional period whether or not their work is the reason for the delay.
Many disciplines finish early. Concept artists, composers and performers may have completed their contribution months before launch, so extra time adds little for them.
Studios move those people to other projects where possible, but reassigning specialists mid-schedule disrupts whatever they are moved onto as well.
Marketing spend is committed in advance
Advertising placements, event appearances and retail promotions are booked months ahead and paid for on schedules tied to the original date.
Some of that spend is unrecoverable, and the campaign built around it has to be rebuilt for a new date rather than paused and resumed.
Awareness generated before a delay also decays, so a portion of the money already spent has to be spent again to restore the position it bought.
Partner commitments extend well beyond the studio
Retailers allocate shelf space, manufacturers schedule production runs, platforms plan storefront features, and hardware partners may have built bundles around the release.
Each of those arrangements has its own lead time and its own penalty for change, and unwinding them consumes management attention as well as money.
Collaborations with other franchises or products are the most fragile, since they depend on a shared window that may not exist at the new date.
The calendar itself is a scarce resource
Only a limited number of weeks in a year are commercially attractive, and the strongest ones are already occupied by other large releases.
Moving a game means finding a window that avoids direct competition, which may be considerably further away than the amount of extra development required.
This is why delays are frequently longer than the work would suggest, and why a game finished in spring might still arrive in autumn.
Financial reporting adds its own pressure
Public companies forecast revenue by period, and moving a major release between reporting periods changes results that have already been communicated to investors.
That makes delays across a financial year boundary considerably more consequential than delays within one, independent of the development situation.
The pressure this creates on release timing is one of the less visible reasons games ship before they are ready, and it operates entirely outside the studio.