I think PS4 will soon loose against the Wii in this competition but it will have the final victory.
Wii was a beast unmatched until sales fell dramaticaly from one year to another, while I expect PS4 to be supported for a long time just like the PS1, PS2 and PS3 and having strong sales that in the end will put it ahead of the Wii
I think there is actually a chance of the PS4 keeping up with the Wii the first year up until the holidays. It was 2008 were Wii really took off and started selling 300K+ most of the year.
With enough supply and Japan launch and some big titles to go PS4 could build a lead of about a million by the end off March.