The best thing is: The PS4 Sales Figures are awesome for every publisher and gamer. More and more great Games coming in future. Highlights and AAA-Games, Blockbuster, Indie-Games and many more :) Good for us =)

Nintendo competes asymmetrically, but that doesn't mean they aren't competing. For whatever reason, the market always demands new systems within about 5-6 years, and manufacturers need to launch within about a year of the competition. One of the major reasons they do this is for developers. If one waits too long, they won't be able to attract developers to their systems. The companies don't want to learn a new hardware when they have no idea what the install base will be and the other system(s) already has the install base they need. Sony can't play in Generation 8 forever. They have to move on.

To directly address the topic "Why won't it sell 100 million," is to ask why the PS4 has sold as well as it did. If you compare consoles sales to the same time last generation, you'd see hardware sales are down. This means Sony's growth is not doing to bringing in new customers but by consolidating the remaining ones around Playstation. Sony now has competition with Switch which is doing very well. Because handhelds do so well in Japan, Japanese developers will focus on it over Playstation. 

The question is do customers who have, thus far, stayed out of Gen 8 want to jump in now or would they rather jump into Gen 9. My expectation is consumers will go forward (thanks in part to an improving economy). They will either invest in Switch or wait for Sony and Microsoft to release new machines. Again, if Gen 9 didn't start I could see 100 million. I think its too late. 

Thats a lot of units sitting on shelves

COngrats PS4 .

Greatness  awaits !

I didn't say they weren't competing, they're just not doing it directly in the fashion of the PS4 and X1. They've released a system with an interesting concept, but the end result of that is its hardware is poorly suited to much of what 3rd parties offer. If the Switch ends up lacking western support parity with the PS4 and X1, i don't see its overlap being hugely significant.

The drop in hardware sales seems to be predominantly down to Nintendo's loss of the new market they generated last generation. The PS4 and X1 are currently tracking 20m+ ahead of the PS3 and 360, and while i do expect the leaders of that gap to eventually reverse, it seems unlikely that the PS4 won't at minimum reach near 100m.

I agree the Switch is likley to receive a lot of Japanese support, but what's interesting is that we might see that work both ways. With many Japanese developers paying more attention to the west, and with the Switch representing the jump to HD development for many of them, there's a good chance many previously 3DS only releases will start appearing on both the PS4 and Switch. We saw it a lot between the Vita and PS4, and that was a more difficult porting process than Switch to PS4. A decent number might even end up on PC.

Overall i think we'll just have to agree to disagree. I'm personally expecting the PS4 to sell 95m - 105m, but this is ultimately a discussion that time will answer ^^

i think: 108 million lifetime :)