Well i guess i had your memorization skills.
Chess is all about memorization and it's boring

I think it was Josh Waitzkin (Searching for Bobby Fischer movie and also creator of Chessmaster series) who said that a player can actually get pretty good in chess off memorization. However, he goes on to say that memorization will only take you so far. At some point you will have to adapt and learn solid tactical strategies to be really good.
My guess is memorizing openings and endgame strategies will bring most players to about a 1600 rating on here. Thats just my theory tho from personal experience.
My guess on the other hand, is that it can get you to about at least 2000 here (for blitz). Below 1600 that you mention are mostly all the ppl (including me) with mediocre chess memories, or ppl that haven't played for long time. If someone has exceptional memory, he/she will most probably get past 1600 pretty fast with a moderate effort.
Memorization btw, is not just openings. Almost everything in chess apart from positional play, has strong connections to some kind of memorization (patterns, tactics, calculation, visualization, remembering previously played games and positions, intuition etc.).
Being strongly related to memory doesn't make chess bad though and at the highest levels (I mean GM level and not 1600 elo) everything counts. These guys need to have exceptional memories, be exceptional tacticians, have amazing positional skills, stamina, be very strong psychologically..
It is what it is (and I like it)
Im near 2000 blitz and i can tell you for certain that while memorization does play a big part, it is NOT whats helping me win games. Theres midgame strategies that have nothing to do with memory that usually decide the winner in most of the games i play. Memorization comes in handy in openings and endgames, midgame you can never predict because every games different. Tactics skills comes in to play for the midgame.
It is partly about physical strength.