With any project set up, they want to sell and reach the maximum. Because, it gives them the assurance they handle the next process to bring the development to the project in the long run. Therefore, when the market does not have the best support conditions for their sales process. stretching is understandable.
Sometimes get happened that an ICO announced their extension of the project being develop due to not able reach the soft cap during private sale. But this doen't mean that the project were having a poor support from the investors but rather investors wait for the right timing when this projects gets in demand with its great development arises in the long run of bounty project campaign. That's why sometimes ICO period gets long but it means more profits and great rewards.