"Third-party developers are usually called upon by a video game publisher to develop a title for one (or more) systems. Both publisher and developer have considerable input in the game's design and content. However, the publisher's wishes generally override those of the developer.
The business arrangement between the developer and publisher is governed by a contract, which specifies a list of milestones intended to be delivered over a period of time. By updating its milestones, the publisher verifies that work is progressing quickly enough to meet its deadline and can direct the developer if the game is not meeting expectations. When each milestone is completed (and accepted), the publisher pays the developer an advance on royalties. Successful developers may maintain several teams working on different games for different publishers. Generally, however, third-party developers tend to be small, close-knit team. Third-party game development is a volatile sector, since small developers may be dependent on income from a single publisher; one canceled game may be devastating to a small developer. Because of this, many small development companies are short-lived."
Qouted from http://en.wikipedia.org/wiki/Video_game_developer
I can understand the importance of milestones and a deadline but sometimes a game needs some more work. A company can choose to release it anyway fully understanding that could irk the consumers or they hold back the game and probably some people within the company.
I think it just depends on how the developer and publisher relationship and how each company likes to run itself.
