I think the answer about this question is totally depends on for what that person using his/her laptop mainly. I have Mac book pro retina, and was using drawing/painting(Adobe Photoshop/illustrator), and also creating music by using Logic/GarageBand. After I got iPad Pro, I barely need my MacBook Pro, won't carry it out to cafe anymore, only for home use. Instead, I'm carrying my iPad Pro, all digital painting/drawing and photo edit has a been done on it, some part of creating music also has been done on iPad Pro as well. When I need to mix down sounds and music, I anyway need better sound system which is not possible to bring out to cafe, so I'm gonna do it at home anyway.
So for me, yes it almost replaced my laptop. But if you're some one who works for those music composing, your laptop works much better and you need it, if you use your laptop for business, I think it's possible still you feel it's better to use your laptop for it. If you mostly use your laptop for reading emails, chatting, photo editing(as hobby), web brousing, watching movies/TV and listening music, reading ebooks, then iPad Pro is more than just "replaceable".
I agree that iPad Pro having some weak apps issues, I'm having hard time to find great music crating apps on iPad Pro, so as video editing, but I say somehow there are lot of good painting/drawing apps and some photo editing apps. maybe that is because more "common use", and depends on popularity.
I don't think they bring in full versions of Final Cut, Logic Pro to iPad Pro or whatever their future iPad series, unless somehow sometime in very far future, the time there's no desktop/laptop exist in this world comes. They want to have kind of different purpose of use for each ; desktop, laptop, iPad, iPhone. And since one of iPad selling points is about how thin and mobile it is(compare to laptop), technically it's tough to let iPad carry all necessary memories and hard disc drive to take care of those heavy work.