Of course this is the case, Phil Harrison said so himself back when the PSP was releasing and was made plainly clear by these statement:
"The idea of a handheld rivalry with Nintendo is an irrelevance, those formats don't appear in our planning. It's not a fair comparison; not fair on them, I should stress. That sounds arrogant, maybe, but it's the truth."
"Nintendo knows its target audience, because it has really narrowed that down; and it's pretty much defined by a boy or girl's ability to admire Pokemon."
So they knew from the very beginning that the DS was not even worthy to be considered a serious competitor. The demographics of the DS is obviously pokemon lovers while the PSP is everyone else.