Not sure about that. I remember last gen it looked like the Wii was going to smash the PS2 sales, it didn't. It looked like the 360 and PS3 will both reach 100 million, it did not happen either.
When there is a new gen there is excitement that impacts current gen consoles sales. PS4 might just sell 10 million units a year next fiscal year and 8 million the year after. So 120 million is not a done deal yet. However, I think it will reach it by end of 2021. But the PS2 and DS are completely untouchable.
The Wii and even the 360/PS3 are awful comparisons though. The Wii had horrible software support in its last few years, since what third party support it had previously received had moved on and Nintendo itself was shifting resources to the 3DS and Wii U. And the casual crowd had moved onto smart phones. While the 360 and PS3 honestly just felt archaic by 2013. Not to mention the PS3 was held back by its price.
People have been predicting PS4 sales would drop off for years, even Sony have underestimated how well they'd do a couple times, but it's still selling incredibly well and I can't see any reason why that would dramatically change. Sure, it's hit its peak and will continue dropping from here but only 10m next year? That's an enormous drop, I think the only thing that'll hit sales that badly will be the PS5's launch and I don't think that's coming till 2020.
Anyway, thanks for the estimations and updating the title, Zhuge. This has been a really interesting thread. I wish Sony would just be more open with the hardware sales of their previous systems, like they used to be in the early 2000's. I can understand why they'd want to obfuscate the Vita's sales but now that it's basically been put to pasture, I don't really think they have anything to hide any more.
