The only reason there was no demand was that despite the screen size of 17" and resolution of 1920x1200, the specs were identical to the 15" with identical performance, yet they charge 500 pounds extra for it, thats why few people bought it - Apple were happy to fleece customers. The dells of the time however Charged an extra 50quid. There was a clear market for the 17 inch, the Professionals who needed them for Video and CAD and 3d modeling. Some of the Gaming Laptops 15 inch are same or superior specs than Mac 15, with 4k screens, broadwell 5700hq i7, PCI express sata drives, Nvidia 970m, numeric keypads, at at less than 2kg and very slimline (and cheaper) but ALSO make similar 17models, also very limline and barely 2kg with Nvidia 970 for the same price. Apple could easily do similar and I think might still. But at the moment they are focussed on iphones, expensive gaming laptops (theres nothing professional about the mac pro with its gaming cards), and ipads. It has forgotten the Professional Market. The Mac Pro sells in smaller quantities than the 17in Mac Pro ever did so why didnt they ambandon that too??
I just bought a 17inch professional MSI laptop, ultra thin with 960m and love it. I hope I love it as much as my Mac Air from 2011 still going like new, or my NEC P8210 from 2006 still going like new with a recent SSD upgrade and serving my mother well as internet and skype machine.
Come on Apple, listen to your customers.