Like you say, a single product line (iMac) can target both consumers or Pro. Steve wanted to make each line obviously target one type of market without any ambiguity or overlap.
Now even the MBP line is weird. The 15" targets Pros while the 13" is more bought by regular consumers. IMO they should have kept the "MacBook" name like in 2008, so that all MacBook Pros continue the trend of PowerBooks and represent Apple's high-end laptop offering with the best CPUs on the market and discrete graphics, while MacBooks aims the mainstream consumer market who don't need that much power.
Instead they messed up the naming convention saying the 13" MBP was "Pro" since it now had FireWire and an SD card reader, even though past consumer MacBooks already had FireWire and that SD is a consumer format.
IMO the best radical simplifying we could have would be to discontinue everything except the 13" MacBook Air and 15" rMBP, and just call them MacBook and MacBook Pro, respectively. A single 24" iMac model could do the job, and I would also discontinue the iPad 2 and one of the two older iPhones.
We would have something like: MacBook, MacBook Pro, Mac mini, iMac, iPad mini, iPad, iPhone 4, iPhone 5... Basically two of each.
