Well. I for one can say that ive probably spent quite a lot more time studying than playing actual games. In fact i had already finished reading 2 books before i played my first game against a human. I can only estimate, but i would say that the total number of (19x19) games i have played is <250.
In that time ive had a sense of slow but steady progress, that got me to 9kyu so far (SDK yay 
). The only time i felt i had plateaued was also when i played the most games by far. They were fast games against AI, and i found them neither helpful nor fun to play, which is why i left them out of my estimate and stopped doing them so i wouldnt get tired of the game. But that could also be because of this:
However i do feel quite strongly that i would benefit from playing more than i currently do, so this question is very interesting for me as well!