I think the point is that for that generation, MS managed to grow their install base significantly while Sony managed to shrink their user base significantly. So the generation for MS was a great success despite the early onset of RROD while for Sony the PS3 was, if not a disaster as they managed to stabilize and stop the bleeding over the course of the generation, was certainly not a success.
Of course, then MS went and threw all that in the dumpster with the next generation.
And now we have a generation that is in a weird situation where production capacity is the primary driver for the size of the install bases of the two console makers instead of demand for the consoles being the primary driver.
Whoever can secure enough supply of components for their console will be the one with the larger install base over 1 year after launch.
Regards,
SB