Like the featurelist, basic system requirements, and screenshots? How much of Windows, Linux distros, the BSDs, Solaris or MacOS do you see before a new release?
A lot more than that. Before Windows is released, there are reviews for years ahead of time on various websites. There are streamed videos of how it works. There is a tearing apart of it's inner workings and dissection of every click and mouse movement.
Before a major Linux distro update is released, it is given sneak previews by almost every major linux outlet, the same level of dissection as Windows *if not moreso*, and generally total analysis of the design for months beforehand.
Same goes for the BSD's and Solaris.
And *ALL OF THEM HAVE PUBLIC BETAS RELEASED MONTHS IF NOT YEARS AHEAD OF TIME.*
You're the one that asked, just remember.