No ... Really? Is this a supposition, or did you do a survey?
So, DeSean Jackson kept $250k cash (along with valuable jewelry and unregistered firearms in the form of semi-automatic handguns) at his home as a hedge against bank failure a la the Greek debt crisis? Riiiiiiiight.
Look, the burglary in itself doesn't make him an idiot. But I'm willing to bet that Jackson's hip-hop gangsta wannabe social identity had more to do with noted items held in his domicile than tutorials at Fidelity Investments. I'm also willing to bet that Jackson wasn't terribly discrete about his "bling" while chillin' with hangers-on out on the town. Someone knew the money was there.