There may be an element of intentional friction in the lack of a convenient off switch, especially if there's money to be made by keeping you on the hook. However, I don't think you can rule out developer enthusiasm for the "fun" bits of a project and management/bean-counter pressure to deliver products sooner rather than later as a contributory factor. It's the same set of circumstances that give rise to, for example, database applications that don't provide a clean way of managing data volumes or out of date information.