Agreed, not necessarily declines, but poor decision making at Sony. They likely hurt the images of their respective franchises, though.
PD just did what they always do, 2 GT games in a generation but they usually release them before the new playstation consoles are out, so this time it's probably going to bite them in the ass more than usual. They would be screwed without Europe.
SSM really was a weird choice, since they have several teams and do a lot of co-development in other games. Should have just skipped Ascension entirely and continued co-developing stuff on other platforms and start ps4 development.