This is an interesting graph. So by the time we reach May 2012, 360 will have cut the Wii's lead by almost 4 million in two years. Assuming that the 720 (or whatever) launches next year, the 360 could get within 1-2M of the Wii LTD in the US. Would that be the closest console race ever in the US? How close were the SNES and Genesis?
There are only two logical ways to count a "gen": either count all the sales no matter when they occur, in which case you may have a late "winner" because a console drops out of the race (more or less) for whatever reason - this happened with the SNES/Genesis and could happen this gen.
Or you can decide what time frame the "gen" consists of, but that's arbitrary and you'll find it tough to get a consensus, especially when that will change who "won".
The Wii had its heyday, as did the Genesis, but the 360 could be the late "winner" by virtue of a strong finish, just like the SNES was.
Under the same rationale of ignoring sales post-launch of a new hardware generation...
Who "won" the 4th generation of home consoles..?
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Anybody have SNES/Genesis hardware numbers on them?
I found this retro IGN article, which suggests the SNES did overtake Genesis before the Saturn launched in 1995. *shrugs*
Another thing to note is that SNES and Genesis lifespans were shifted by 1.5-2 years.
By 1994, SEGA had lost substantial ground to Nintendo in America. The two had been fairly close going into 1992, with Nintendo making strong gains against SEGA, thanks in no small part to the fact that every Super NES came with a copy of the acclaimed Super Mario World. According to market data, SEGA had a 55-percent share. But when SEGA started fracturing its audience with add-ons like the SEGA CD and 32X and Nintendo kept on producing triple-A games for its loyal fans, the battle was won. Nintendo pushed ahead of SEGA, which spent all of its 16-bit good will on the ill-fated Saturn.
Overall, I'd say it was a good tie between SNES and Genesis, and between Wii and Xbox 360 ... in North America. SNES and Wii clearly won worldwide.