...if we'll ever find out the real reasons, of course. Anyway, just as a small reminder - about 4 days ago, Apple released the NVIDIA graphics update I mentioned above, and then they made it disappear, 2 days ago. Now, that's a short life for a software package!
One of the reasons, as far as I can tell, is that the patch didn't manage to solve the blinking/flickering problems various users experienced when using the 9400M graphics processor of the MacBook Pros, but not limited to them. The proof is available right on the official forums, where user volvr wrote "Just installed the new nvidia.patch from yesterday....but flickering goes on!"
At last, here's another serious problem,reported by the user allanlance - "I downloaded the update today and regret that I did. The problem for me is now worse. I cannot use my external samsung 22inch monitor on extended desktop mode, only mirror mode, and that is not helpful to me. In extended mode it goes black for extended times, flicking on occasionally to remind me that its there still."
If only Apple would step forward and say the truth about all this... After all, it's easy to make mistakes, somehow easy to fix them, but it's not that easy to admit the truth.