You don't get out much. Just because you have never enjoyed using the full range of what a tablet can offer, you will deny the existence of a useful feature. Take the blinders off and live a little.
As I said, publishing houses use portrait mode. So do artist studios. Portrait display monitors have been available for decades. People use these features on large scale machines, and naturally come to expect them on smaller portable platforms. When one of my daughters attended the SF Art Academy, lots of artists used portrait mode (incidentally, most of the machines were Macs). She went on to become a magazine writer and then editor working for a large publishing firm. Lots of portrait mode editing in the publishing business.
As for me, I use the Zinio app on my iPad to read dozens of magazines. It's simply easier to read magazines in portrait mode, as that is the form factor of magazines. The digital magazines are interactive, sometimes requiring input from the reader and that means using a keyboard. Another app is Goodreader where I have hundreds of PDFs and technical notes, most of which are used in portrait mode. Same for dictation apps, reference apps, education apps, medical apps and finance apps. By the way, I also use a stylus on my iPad, for use in some apps. I have 200 apps on my iPad. You, being a Microsoft bigot, have none, because you are waiting for Microsoft to sell a tablet like the iPad. Only then, will you extoll the benefits of using a tablet in portrait mode.
OK I guess I should quantify something, I do read in portrait mode..completely escaped my mind. However I never feel I need to prop it up or set it down, it’s just fine in my bed. Thats the Asus Transformer Prime..an android tablet. I am excited about the MS Tablet because I like the idea of being able to potentially seamlessly move between my home PC, XBox 360 which I use as a media hub and media player and a portable device. That’s my hope. If it doesn’t work out no hair off my chest, but I do get worked up over what I consider either uninformed guesses or exaggerations over minor things that are actually common across every platform right now. I do know one thing my lab will definitely be looking at these for COAs, tracking, test result and dispersal. MS is the only company that had people who were able to get our scales, BioControl DNA systems and customers integrated without a hiccup.