Have you ever taken a dance lesson? or tried to learn how to play an instrument? When you see or hear the experts dancing or playing, a common response is "I could never to do that. It seems so complex and seems to take years of practice and probably requires some skill one needs to be born with." But that's not necessarily true.
Dance teachers always start with the basics and once students are comfortable, move on. Most training professionals know that learning something new is nothing more than learning how to break a seemingly complex task down into small, comprehensible steps and building in tons of practice. Then, when learners are comfortable with the basics, add on another level of information.
As a trainer and technical writer (and dancer), this is a mantra for me, especially when I am learning new and often complex content. I don't get overwhelmed. Instead, I work with the experts to repeat, decipher, explain differently the information they know until it makes sense to me. Then I put myself in the shoes of the learner to help me decide how to translate, simplify and "chunk" the information, as well as where to build in a practice.
My firm belief is that anything can be learned, assuming (the trainer) has access to experts, knows how to ask good questions, and most importantly, can break it down, allowing learners to learn.