Those who are angry about a 5D Mark III or 1Ds Mark IV not coming out must have very short memories or haven't looked at the product cycles closely.
People. Keep in mind for many years Canon has been around 2 full years ahead of the pack when it comes to camera and sensor development. This has been due to the fact that they make their own sensors and tech. All of it. Chips to Lens.
This changed somewhat recently. The 1Ds Mark III was released in the 3rd quarter of 2007. Nikon released the D3X in the 4th quarter of 2008. Canon released the 5D Mark II in October 2008 which was their answer to the non full frame Nikon D90. The Sony Alpha 900 was also a 2008 announcement.
It's also worth noting that the 5D and 5D Mark II have created a new product segment among consumers that has been wildly popular. Who else was making full frame bodies around this cost? Who is today making full frame bodies at this price point?
Currently in non flagship bodies everybody has been getting pretty much refined technology. Some new things here and there, some old things made a little better.
We are currently right in the eye of the storm where manufacturers announce their big product lines. Sony has gone first this year. You'll likely notice Nikon having a similar offering and maybe one big surprise offering.
Now all of that said, I am ready for an upgrade if it's a worthy upgrade. None of the new bodies have been "enough" to interest me just yet. This is coming from a 1Ds Mark III x2 (one body sold this year) and 5D Mark II owner. Previously a 1Ds Mark II, 1Ds Mark I, 10D, D60, D30, Nikon N90, and Phase One P25 have existed in my bags, in my hands, or on my tripod.
Canon has been working on new sensor tech for the follow up cameras since 2007/early 2008. Think about that. They haven't had to produce anything too new due to the fact that there hasn't been "too much" real competition at any price or at performance level.
We'll know within September or October what's up with almost everybody. With bodies coming October through December. Then likely another product announcement next year in Spring. Then another in Fall. There's no black magic to this. This product announcement schedule has been like clockwork for a long time.