I suppose it's an independence thing - like drummers, who spend their lives learning it
I guess so. I can't recall having the same problem when I first started playing the guitar, but on the few occassions in my life where I had the chance to play a drum kit, I had similar difficulty in synchronising my arms with my feet. Either would be in time, not both.
But I believe that anybody can learn anything if you put your mind to it so I guess it's just a matter of practice.
Reminds me of the definition of intelligence: the ability to walk and chew gum at the same time... ?