Ok... honestly you cannot change the parameters of a race to shoe horn your team into a desired ranking.
More importantly, the reason sell-to consumer numbers are the yard stick by which consoles historically competed is because that is how 3rd party publishers generally made their decisons. The higher install base recieved the most risk. Because of that old paradigm, being a loss-leader was actually a good stradegy (even though I consider the gillette business stradegy stupid and in the long term too easy for competition to exploit) since hardware losses would be more than subsidized by software profits and liscense fees.
However, all of this has changed and can be thrown out the window. Sony was the loss-leader expert and in true sony style - Sony simply took gillette's innovative business plan and applied it to the games industry. The disruption worked well for PS1 and PS2, but both MS and Nintendo have exploited all of the weaknesses Sony's business plan had for masive damage this generation. The Wii is profitable on both the HW and SW side both of which are remarkably cheaper than the PS3/Xbox360 HW and SW which has changed the enviroment completely. MS on the other hand has only increased their market share in 4years of life by a little less than 33% (24M compared to 32M), they remain in second place, but have shown that even with less install base they can increase how lucrative their platform is for developers and publishers by adding other value, such as xbox live.
All in all... install base will still be the measure of success, but it is no longer nearly as meaningful. Just look at Wii, it has the largest install base but 3rd party devs consider it far too risky.