don't be hatin'. there are pros who have never ever been near the second week of a slam who are all stenciled up and logoed out (see michael russell) just as there are pros who are much less attractive who are all stenciled up and logoed out (see bartoli).
i remember way way back in the long ago when jj was #1 and iirc i seem to remember that she and prince were in some sort of a disagreement over here contract. her position seemed to be "hey, i'm no. 1 now and i gotsta get paid so back up the brinks trunk!" whereas their position seemed to be "umm...we'll wait on that". in fact, i remember that jj played the aussie warm-up events with the P stencil but by the time the aussie open kicked off, the stencil was gone and i don't think i've seen it on her racquet since.
furthermore, i think she has been "fooling around" with her sticks in recent years. here's a pic from 2012 and you can see that while it's blacked out, it's got a w buttcap and no o ports
and here she is from the aussie this year, using a blacked out racquet with o ports and a p buttcap.
maybe she can't GET a racquet deal, but if that is the case, perhaps it's because her asking price is more that a company wants to pay. it might also be that she's trying to experiment with her sticks a bit. she might have even gone back to her "old faithful" prince stick. who knows?