As I said, I believe you've been proven to be making things up and not actually ever used a Surface Pro... relying instead on things you've read on the internet. I own a Surface Pro and use it daily. So yes, I'm telling you its not only an acceptable experience, but preferred (for the things I'm using it for).
I've spent whole days doing project reviews where I interviewed people all day long with my Surface Pro in portrait mode taking notes with a pen. And between interviews, I was able to pop on my keyboard and do other work in laptop mode with full function apps. I've been to conferences where again I used my Surface Pro to take notes with pen in portrait mode, integrate pictures of the presentation, and whatever. Its really limitless. I've reviewed office documents, PDFs, etc. in portrait mode and done markup with my pen also. So your statement that the Surface can not be used in portrait mode is completely false.
You seem to be also hung up on apps. I find the Microsoft Office Suite on an iPad to be completely unusable for anything but simple work. I am in complex Excel workbooks on a daily basis, as well as the other apps, Project, etc.. With my external display, keyboard, and mouse, I can get real work done on the Surface Pro. When I go mobile, I can just grab the Surface Pro and hit the rode. I don't have to switch machines, wonder if I have the right versions of files, and then use a cripple version of tools while traveling. I can work straight through takeoff and landing if I wish. Most importantly, I can travel light and have the same environment and apps no matter where I am... not switch between two different OS platforms and input models. Maybe you play a lot of games or something, but with a browser, Office Suite, and a few entertainment apps like Netflix, there isn't really any app I'm missing. If I want to play a game I can do that on my Note 8.