I also believe that anyone can learn anything, though unlike others here, I also believe there is an absolute limit to an individual's abilities in a given subject. That limit likely stems from how each person's brain operates. Naturally, logical people will excel at logical subjects and artistic people will excel at artistic subjects.
For example, I would say that my brain operates 95% logical, 5% artistic. Math and sciences I soak up like a dry sponge soaks up water, languages are not as easy for me to learn, but I still have little trouble doing so.
Artistically, I have spent a good deal of my life playing musical instruments, but I am mediocre at best as a musician, and I have no ability for original composition. Writing; I can put words together just fine (because of my ability with languages) but I don't have the artistic gift for making a story interesting. Drawing; well, I screw up stick figures.
All of those are not from a lack of determination or practice, I just have my own absolute limits to my abilities at them. I keep trying to do those artistic things because, honestly, the ease of learning the logical things makes them boring to me and I'd rather be interested in what I'm doing.