I should have said relative failure compared to the PS and PS2, there's no way anyone can look at the PS3 and call it a success considering the brand went from dominating the previous two generations to "also ran".
PS4 became a marginal success in the end but Sony loss a huge chuck of its market share. The real problem with Sony is the lack of 3rd party sales compared to the XBox 360 and XBL takes in more revenue than PSN. Sony biggest reward with the PS3 has been Blu Ray, which kicks ass at the end of the day.