What's telling is that this is the guide made available to software developers looking to create software for Windows. So this isn't some internal document either.
> This guide is intended for those who are designing and developing Windows-based software. It may also be appropriate for those interested in a better understanding of the Windows environment and the human-computer interface principles it supports.
This section in particular is interesting:
> # How to Apply the Guidelines
> This guide promotes visual and functional consistency within and across the Windows operating system. Although following these guidelines is encouraged, you are free to adopt the guidelines that best suit your software.
> However, you and your customers will benefit if, by following these guidelines, you enable users to transfer their skills and experience from one task to the next and to learn new tasks easily. The datacentered design environment begins to break down the lines between traditional application domains.
> Inconsistencies in the interface become more obvious and more distracting to users. Conversely, adhering to the design guidelines does not guarantee usability. The guidelines are valuable tools, but they must be combined with other factors as part of an effective software design process, such factors as application of design principles, task analysis, prototyping, and usability evaluation.
> You may extend these guidelines, provided that you do so in the spirit of the principles on which they are based, and maintain a reasonable level of consistency with the visual and behavioral aspects of the Windows interface. In general, avoid adding new elements or behaviors unless the interface does not otherwise support them. More importantly, avoid changing an existing behavior for common elements. A user builds up expectations about the workings of an interface
We are talking about a document that is over 300 pages long here. I suppose that if I had to let the cynic in me answer the question about what happened, the answer will probably be costs.
