It sounds to me like if Apple were to add a touch screen to the Macbook Air, then half of the people who bought an iPad Pro would have gotten that instead.
While that may be the case for others, not for me. I got the iPad Pro because I wanted a tablet, not a laptop. Prior to getting the iPad, most of the time I used my laptop was spent watching video, reading forums (like this), reading the news, etc. A smaller percentage of the time is working, and as I own a music production company, most of that time is spent listening to music, and a very small percentage is spent using Microsoft Office programs. Lastly, I did quite a bit of gaming on my iPhone, which is now much nicer to do on the larger screen of the iPad.
So I figure I would have an easier time using a laptop for about 5% of what I do, and a tablet is probably easier for 95% of what I do. Yes, I could keep both if I wanted to, but lately I've been thinking about simplifying things and getting rid of the Macbook and just buying a keyboard for my iPad Pro. But whatever keyboard I buy, it must be easily removable and it does NOT have to be portable. I would probably just use it while at home. For the rare occasions that I need to type while I am traveling, I can get by with the on screen keyboard.
That said, I would prefer a keyboard that uses the smart connector so I don't have to deal with charging the batteries in the keyboard. So for now I'm waiting to see what comes in the near future.