Video game release dates move often, and the announcement usually arrives close to the original date. The timing is a symptom of how the work is structured rather than poor planning.
Systems are built separately and combined late
Teams work in parallel on rendering, physics, artificial intelligence, animation, audio, networking and content, each progressing against its own milestones.
These parts are integrated continuously in principle, but full integration under realistic load only becomes possible once most of the content exists.
Problems arising from interaction between systems therefore surface late, and they are the hardest class of defect to diagnose because no single component is at fault.
Performance problems appear only with full content
A level running smoothly in isolation may not do so once populated with final assets, effects, characters and audio all competing for the same budget.
Optimisation is consequently a late-stage activity, and its outcome is uncertain until measured, since the required saving may or may not be achievable without cutting content.
Certification for consoles imposes performance and stability requirements that must be met before a title can ship, so this work cannot be deferred past release.
Testing scales badly against player behaviour
Open-ended games permit sequences of actions that no test plan can enumerate, and defects often require an improbable combination to reproduce.
Internal testing finds the common paths, while public tests expose the rest, which is why beta periods reveal problems that months of internal work did not.
Fixing a defect found this way can require changing a system others depend on, which reopens testing for everything connected to it.
The release calendar constrains the options
Large titles avoid launching alongside each other, so the viable windows in a year are limited and a short slip can force a much longer one.
Marketing is committed months ahead, and physical production and distribution have their own lead times, so the true decision point precedes the release date substantially.
This is why delays are frequently announced in multiples of months rather than weeks, even where the remaining work would take less time than that.
Patching changed the calculation but not the problem
The ability to update a game after release means a title can ship with known issues and improve afterwards, which has made shipping on schedule more feasible.
It has also raised expectations of launch quality, since a poorly received launch now generates a durable public record that continues to affect sales.
Studios therefore weigh a visible delay against a difficult launch, and increasingly choose the delay because its reputational cost fades faster.