In a new article at the MSDN Blogs, Microsoft admitted that the decision was a mistake:

“We heard from you that our decision to not initially release Windows 8.1 or Windows Server 2012 R2 RTM bits was a big challenge for our developer partners as they’re readying new Windows 8.1 apps and for IT professionals who are preparing for Windows 8.1 deployments. We’ve listened, we value your partnership, and we are adjusting based on your feedback. As we refine our delivery schedules for a more rapid release cadence, we are working on the best way to support early releases to the various audiences within our ecosystem.”

Although Windows 8.1 reached the release to manufacturing stage, it doesn’t mean that the operating system is cooked. Microsoft continues to improve Windows and new updates are even scheduled to deploy on October 18th, when the company plans to make available Windows 8.1 worldwide.

Source Blogging Windows