You could compare it to learning to sing or learning to dance. We can all dance, we can all sing. But if you want your original talent to grow and expand, if you want to be able to draw in a way that you can't now, you begin another journey.
After I received my post graduate degree in visual arts, I discovered that I couldn't paint the way I wanted to. I had to find a school that taught traditional skills. My teacher told me, six years to learn to draw.
This was strange for me to hear as I thought that I already knew how to draw. I had been a graphic artist before my return to university, and had always been praised for my drawing skills. I knew that I wasn't skilled in painting, but I thought that I could draw.
My teacher then took me on a 4 year journey relearning how to draw, and beginning a journey to learn how to paint. I had to actually unlearn many of my habits around drawing. That was painful.
What I discovered was that I had been on a deadend road in my drawing. I would not have been able to improve. After she had tutored me, I was on a new road, one where I could continue to grow and develop as a draftsperson indefinitely.