Canon has a history of not producing cameras that will 'eat their lunch'...Which makes it a company culture almost.
Canon is not a camera company. don't anyone forget. they are a flipping huge conglomerate with many markets to satisfy and a whole lot of internal politics as well.
A company in the lead will not, in almost any circumstance, put their best tech on the market until the competition forces them to do so. Let's say we're on Generation N technology now; if Canon jumps straight to Generation (N+3) for its next pro camera, there are two problems:
1. They miss out on the opportunity to sell Generations (N+1) and (N+2), and lose the profits therefrom.
2. They lose their R&D incremental investments in those intermediate generations (yes, some of that goes into later generations, but some does not)
In other words, Canon will not sell sensors with 15-stop DR in their SLR's until someone else starts selling a lot of sensors with 14.8 stops of DR. Just ain't gonna happen. It's a business, nothing else. This is why we should all be cheering the D4 and D800: it will force Canon's hand.