What I'd like to know is the real install base of the three consoles. You know, not every Xbox360 sold is actually going to a new customer due to a so-called RROD phenomenon. Is there any good data to clear that up?
The real install base doesn't matter, what matters is the amount of revenue (and profit) brought in by additional software and service purchases. This is what is known as attach rate, and the Xbox360 has a rather exceptionally high attach rate. And this is from a console which has long been hacked to run pirated/copied discs (the PS3 has not been hacked, which you would've thought might attract more game developers). I've always been shocked at how good the Xbox360 attach rate has been.
If half those Xbox consoles are landfilled due to RROD or other failures, then it just makes the real attach rate that much better and even more surprising. Despite the crap hardware and piracy, the Xbox360 is certainly moving software like mad.
P.S. PS3's suffering is not just high retail price, but apparently also the relatively sub-standard dev system which Sony provides. Essentially, the thing is a giant pain in the ass the work with, so dev houses won't spend the extra man-hours necessary programming for it.