Put down the pitchforks -- at least for a minute -- and consider this:
Point 1: Yes, it's true: This is not how Microsoft has rolled out the final Windows bits in the past. With previous Windows releases -- even Windows 8 -- Microsoft RTM'd the bits, handed them off to OEMs, and made them available to MSDN/TechNet and volume licensees a couple weeks later. These groups got the gold bits a month or more before Microsoft "launched" the new release and made it available at retail. Starting with Windows 8.1, this changes and everyone gets the gold bits at the same time.
Point 3: Microsoft doesn't "make" Windows like it used to. Instead of spending 2.5 to 3 years planning, developing and testing a new Windows build, Microsoft did all that in 10 months this time around. Consequently, the company will be patching and updating Windows 8.1 and all the bundled apps that come with it (Mail, Calendar, the core Office apps, the Bing consumer apps, IE 11) right up until the launch. Microsoft will push updates to the whole shebang just before customers can get their hands on the final bits.
Point 5: The decision to withhold the RTM bits until launch probably does mean more folks will be downloading non-official RTM builds that have already started leaking ahead of October 18. Microsoft's advice is, unsurprisingly, users should wait for the "official" RTM bits and expect possible patches and updates to the consumer preview builds that the company released in late June in the interim.
Developers and volume-license customers: Do you see delaying availability of the gold Windows 8.1 bits hurting you in any way (after reading the points above)? And remember: I am just the messenger here.