Twiggy, it is very simple. He had tons of funds in the summer, but only to buy players that Valdano and Perez approved of, and they specifically refused to sanction the purchase of a striker, while happily shelling out for others, including Psuedo-Galactico Transfer-Muppet Flavour-of-the-Month Ozil.
It was not like here at United or at somewhere sane where the manager is given a transfer budget and can buy whatever he wants as long as it falls within the budget. His spending had to be approved, both for its amount and for its content.
Surely you understand that he's going to strengthen every area of the squad that he can, even if the board refuses to let him strengthen other areas?
Of course his track record of walking out isn't very good, and you can argue he should have known this was coming, but that's a totally different point from the issue of wanting a striker in the summer and specifically being told "no", only to now see the club with only one recognised striker, and he largely considered to be unreliable after a tough year and a half at Real.