The Wii hasn't managed to break 50% yet... its even losing ground ever so slightly. This makes sense, since, as time marches on, the HD consoles are even more appealing -- more HDTVs are in homes, PCs get faster and faster... The Wii looks older and older (as do the HDs, but the Wii is lagging even more)...
The Wii's market disruption was based on blue ocean friendly demographic appeal -- that splash has made its mark. There are no reasons for it to suddenly become more popular, like there are for the HD consoles (i.e. cheaper HD consoles, and more HDTVs). Unless the Wii gets a price drop, and soon, I don't think it will ever hit 50%.
Week-to-week sales of the Wii outside America are closer to 40%. The dollar is super weak, and will remain so for a while... no price drop. America is also, next to Japan, probably the most prone to HDTV adoption increases, once the recession is on the downturn -- the new digital TV thing this year will get a LOT of people doing upgrades, even if there is a program is adapt your old analog SD set.
Unless Nintendo blows us all away with new awe-inspiring software at E3, I think that the 50% marketshare number, no matter how close it is today, will not be achieved. Games like WiiSports Resort are not system sellers -- its a refresh of WiiSports, and isn't any more appealing than the original, if you don't already own a Wii.
