It is beyond unlikely that the Ps3 would catch up with the Wii. When talking in terms of it catching the 360, there is a respectable chance of that battle going either way. The Others chart could end up being the swing vote.
I have to agree with Rol and Happy that early momentum is extremely key to the overall success of a console. It's far from the only factor but it's importance can't be denied.
"But as always, technology refused to be dignity's bitch."--Vance DeGeneres