Europe is PlayStation land.
Japan is Nintendo/PlayStation land.
US is the only place I could see growth for next gen.
I mean, they all fight for the American market, but in Europe while Playstation is bigger than the other brands by a measurable margin, Nintendo's market in Japan is over twice as large as Sony's, so not sure you can call Europe Playstation land, but not call Japan Nintendo's, every week this year just about, Nintendo has sold over 70% of the dedicated hardware in that country.
Another way to look at this is that Sony is the only company to have a strong presence in all 3 major markets, which is why their consoles always sell so well. Nintendo has a strong hold on 2 and gaining ground in Europe, while Xbox has a strong hold in America and some success in Europe, but Japan is outright hostile to the Xbox brand, maybe the solution is to partner with another Japanese publisher to create a new Japanese brand for Microsoft's console there, someone like Sega "returning" to the market, by releasing the Xbox there as some sort of Mars box or whatever Sega would name a new console. This idea btw, is what Nintendo almost did with Atari for the launch of the NES.
Also, I think Europe is the country that needs to see growth from both Microsoft and Nintendo, Switch seems to be doing well there, so that is good, but it's probably the most important market for them to gain ground in. Sony needs to gain ground in Japan, PS4 a much more successful system, at a much more reasonable price, is at best flat with the failing PS3. The Vita also failed heavily here, so it's important for Sony to gain ground in Japan IMO, but they will likely continue to put out 100 Million selling consoles regardless.