Wouldn't it be nice if it was just 'desire' alone? I have experienced that with music. I have the 'desire' but not necessarily enough 'talent' to gain the momentum that I would like to have in order to call myself a musician. At the same time, I have learned that practice, practice, practice does improve on the outcome and I am getting better at the craft.
I think it is much the same with writing. There are those who are schooled in the mechanics of it but lack the emotion and creative edge to put the tools to work. When they do, they come across a 'mechanical writer'. To some degree, I think there are some who are born with natural talents that work well in writing. When they add some formal training to that, it tends to work although sometimes the emphasis on employing the tools can easily overshadow the creative intent of the writer.
Thus, I think it comes back to finding a 'balance' between to tools of writing, creative inspiration, emotion, and awareness of your reader. When you can orchestrate those items in proper balance the end product is usually very good.