My point is, what does 'the most popular' tell us?
In a nutshell, the Wii sold the most, and so therefore it is the console that sold the most. The PS3 and the 360 sold the same number of units, and so they each sold the same number of units as each other.
Yeah I do agree with your points about it not being the most useful statistic.
Off the top of my head though, I imagine it tells you a lot about your market demographic. For example if the Land Rover is more popular than the BMW, then perhaps car buyers are more interested in driving off road in the country? If the Wii is the most popular console then that suggests the market prefers shit casual family living room gaming.
Sounds like very useful information. And you can bet all the console manufacturers have spent a lot of time looking at what has been 'popular' this gen to predict what is going to be 'popular' next gen.