(Mk III is not a replacement but and upgrade to higher level, like a new line)
I disagree, the 5d3 was the intended replacement (hence the name), but Canon screwed up because they didn't account for the competition and now have to put out another camera body. If it wasn't for Sony and Nikon, the 5d2 would probably already have gone and people would have to decide either to pay $3000+, stick with a crop camera or wait a 1-2 years for the price to drop. Hail to the competition!
I agree with the latter...but yet disagree too. 5d3 is the replacement for the 5d2, that is certain. But I don't think canon screwed up. I think of it like this. If you advertise your cost for lets say wedding photography at $3500, and the other guy, your competition who is just as good as you (better in some ways, but worse in other's starts targeting your clients and telling them they'd do it for $3000 is it you that screwed up your pricing...or, is the other guy in fact undercutting you by offering a similar deal for less $$$?
I bring this up because in almost every pricing discussion for our work, those that charge too little are called bad names --- it's frowned upon. Some even go as far as saying its part of whats destroying professional photography. So in a real world comparison - if you believe your work is worth every penny of the $3500, do you lower your rates and profits and match your competition or do you stick to your guns and maintain your rates?