“Memorization” is in quotes because the goal of studying is not to memorize something like you memorize a sequence of random numbers…
Instead, you want to know something intimately in multiple dimensions. Knowing transcends mere memorization; it is deeper and broader and all encompassing. Such intimacy with the music is achieved by getting its patterns and essence into your eyes, ears, brain, heart, muscles, and soul by tapping into all aspects of the music: sight, sound, thought, motion, and emotion.
I used to struggle greatly with “memorization”, but now I realize that my problem was not “memorization” at all. The problem was that I never truly learned what I was trying to learn in the first place! It is not possible to forget something I never learned to begin with. And I didn’t truly learn it because I never truly studied. This is true for all of us with supposed “memory” problems.
The solution, of course, is not to practice “memorizing”, but to study more effectively.