That's a good question - to be honest I'm not sure I have the answer.
I have personally never thought of myself as creative. Throughout my entire childhood, I had never expressed any sort of artistic savvy, and even today I find that my work lacks that tiny bit of subtlety to really consider myself an artist.
My personal journey was definitely one of simply banging my head against the wall so many times that I eventually found the way around it.
As someone who enjoys solving problems (perhaps as a result of the engineering background), creating images that are visually compelling and exciting to design, complete with a catchy storyline - was just about figuring out a formula and constantly tweaking and improving it.
My opinion: I believe that creativity can be learned - all you need to do is never be satisfied with what you create, and sooner or later the work eventually becomes better than the 90% and you become known as "a creative".