"Ken Kutaragi's retirement has to be considered as an offering to shareholders who are understandably upset that the hugely expensive PS3 has failed, so far, to look like the all-conquering platform Sony had hoped for."
That's the view of GamesIndustry.biz who look at what needs to be done to improve the market standing of the PS3. They single out the price point and lack of compelling new software as the biggest problems.
They also say that investors do not care that much how the PS3 performs against the 360 or Wii but instead how "it stacks up compared to the sales curve of historic Sony products", i.e. the PS1 and PS2.