because the cameras people already have are firewire and they dont want to by a cheaper usb model
Because I own 2 cameras, and 1 external hard drive all of which are firewire based and they work great.
People used to get hung up on the USB vs. Firewire debate, which is basically pretty lame, but if you remove a connector spec that is still in pretty wide usage, that is a big deal. You better be certain that the removal doesn't serve as a "differentiating factor" against you.
I'm old enough to remember when apple replaced the ADB connectors for USB. You'd of thought the world was ending for some people, but it was the right move, and it needed to happen sometime.
I'm not sure if there is a parallel between that and firewire or not (I would say not, at least not yet). I for one think firewire as a standard still has a lot of legs, and you won't see Apple abandon it anytime soon, certainly not on the pro hardware.
Which means that either the spy photos are wrong, which is a possibility, or that Apple is trying to differentiate consumer computers vs pro computers by supporting more connection types on their pro line. Especially now that the pro line and the consumer line are both rumored to be made from aluminum, they will need some "differentiating factors". The firewire ports could be one of those, but I myself think that would be a mistake on Apple's part. Differentiate with CPU/GPU, and ports like eSata, not ports like firewire.
I guess we'll all find out on Tuesday.