I never mentioned a gap at all, did I? No, I'm not expecting anything right now.
The only things we can settle with all likelihood at this point (in my opinion), are these;
1: The xbox will probably remain the strongest in North America for the 8th gen
2: The One will probably have a really good first week in in North America and some parts of Europe, so the difference initially shouldn't be massive
The facts so far are;
1: The PS4 did extremely well at release in North America
2: That fact means that Europe will be getting a smaller shipment than they could probably sell off, seeing as how we know Sony are poised to produce about 5 million units until the fiscal year ends
3: Japan will be lost to the xbox, that's a given
Too soon to conclude anything for now, but the way it appears right now, the One needs some serious muscle to beat the PS4 out of the gate. The higher price point and staggered launch won't help either. Given, the PS4 also has a staggered launch but it excludes Japan for now while the One has large chunks of Europe and other areas that will go without One's on the shelves for 2013.
PS: I still maintain that the 8th gen will be smaller than 7th gen, both in software and hardware sales on handhelds and home consoles.