You’re correct I missed you saying portrait mode. Who uses there tablet in portrait mode? Especially in a typing situation? I never ever use my tablets in portrait mode except when I play words with friends or scramble, other than that it doesn’t provide much use. If you are going to use it, say as a student, or a doctor, then yeah you would use portrait mode for note taking...which is why they offer a stylus(MS One Note is second to none out there), other than that like all tablets they are primarily designed to be used in landscape.
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.