Indecent Exposure wrote in post #12263725
A 5D with a state of the art AF should no more eat into 1Ds sales than 5Ds already do. The jump to 1D(s) should always be about more than AF. If crippling the 5D's AF is the only thing protecting the 1D(s) market then Canon did something wrong designing the 1D(s).
I think you may have missed my point. You really need to compare market sharing between 5D/1Ds and the 7D/1D. I think it's throwing an apple into a basket of oranges by looking at the 5D/1D/1Ds bodies together.
Why? Because you have to look at the full frame bodies and the crop/sports cameras separately. A 1.3x sensor is much closer to a 1.6x crop sensor than it is to a full sensor. Truly speaking the 5D should only eat into the market share of the 1Ds series. The 7D eats into the market share of the 1D series.
That said, for the 1Ds to retain it's hold on professional full frame users, Canon will focus on producing incredible resolving power with clean images are incredibly high ISOs. The ergonomic unibody design with complete weathersealing is the lynch pin for a lot of professionals.
For the 1D series, Canon will probably keep improving fps and AF in these bodies. Sensor technology will trickle down and they will continue to improve in that area, but image quality never "catch up" to the 1Ds series.
Arguably, however, there will be a point where people will ask how much is enough and these cameras will be so amazing that no one needs the uberhigh ISO. At that point, it will be about other bells and whistles in body design and perhaps even in areas such as video capabilities, built in wireless file transfers or flash triggering capabilities.
There are a lot of factors at play, but the marketing department and engineers will be able to keep differentiating. If APS-H is on its way out, it should still be around for quite a while I think.