I have no idea where you picked up this misguided and downright incorrect view of chess. There is minimal memorization all the way up to and past master level- I perhaps know a few opening lines, up to move 7 or 8.
Then again, it perhaps depends on what you deem memorisation. When you do tactics problems, you are effectively learning the patterns that can arise, which might be deemed memorisation.
But no matter how much this comes into play, chess is all about improvisation- at least my games seem to be! Nobody plays like a robot, and the game certainly does not come down to who has memorised the most lines, no matter what level you play at.
Once or twice I tried to begin playing chess, but what seemed to me(I'm not sure yet) the predominance of theory memorization over strategy or tactics kept me away. I didn't want to use 80-90% of my chess time memorizing positions.
Also, I got the impression that evolving in chess meant going in the direction of a memorized game, since I could find games played to the 30th move without leaving the book. It just didn't make any sense to me to play a game which would be become less fun the better you got, which would mean that learning to play better would spoil the game.
Ok, this was my impression then, but after reading some more opinions, it seems that I may be wrong and I'm thinking about trying to get into chess once more. Anyway, before doing this I would like to hear opinions of people here as to the extend memorization importance in chess. After attaining a good playing level, do we still have space to improvisation, to creativity in terms of tactics and strategy, or do the game become pre-programed and the winner will be who master all the lines of the positions showing up on the board?