This has been on my mind for a while now. I would like peoples opinions. I personally believe that poker is purely based on experiences and situations which you learn from. Yes people will learn from situations faster than others due to memory but apart from that...
Also determination and hard work obviously play a part in grinding all day and needed to keep motivated to keep learning but I also think that these are traits which are learnt from past life experiences and not naturally given. For example, Phil Ivey spent time on the streets in Vegas when he lost big which therefore gave him the determination and focus to become a better player. Manny Pacquaio, Zab Judah, James Kirkland etc.. (Boxers) lived rough when young and this gave them the determination to graft hard in the gym to earn as much money as possible... you get the idea. Obviously boxing needs natural ability but I am refering to the determination element only.
As you said, memory is an important part of every poker player. And It's a natural skill. But as everything else, such abilities can be trained and learned.
I would say that experience is a much bigger factor but natural skill makes a difference as well. The math comes to some people a lot easier than others, and I think that aspect is probably more of a natural talent than memory based. The math can also be a lot more creative than the sort of math you learn in school.