> There are huge differences in drawing ability, but going from "I can't draw" to "I can draw quite well" takes days, not years
Maybe for some people, but not everyone.
I have developmental dyspraxia, a.k.a. developmental coordination disorder. I'm never going to be good at anything that requires fine motor control. Maybe at best I could get the first few strokes of a drawing to look good, but after that it's going to fall apart. I know this from my experience with seriously trying to improve my handwriting back when I was 24 because I was tired of writing chicken scratch all the time: I can now make the first few words of a paper—maybe if I'm lucky even the whole first line—look fantastic, but after that I just lose any sense of alignment and proportion and everything starts slanting in random directions and changing size all over the place. [0]
It is a medical condition, and there is no cure.
[0] This image on Wikipedia sums up my handwriting pretty well. It's specifically about motor dysgraphia [1], which is part of my dyspraxia. https://en.wikipedia.org/wiki/File:Dysgraphia.jpg
[1] From https://en.wikipedia.org/wiki/Dysgraphia
> Motor dysgraphia is due to deficient fine motor skills, poor dexterity, poor muscle tone, or unspecified motor clumsiness. Letter formation may be acceptable in very short samples of writing, but this requires extreme effort and an unreasonable amount of time to accomplish, and it cannot be sustained for a significant length of time, as it can cause arthritis-like tensing of the hand. Overall, their written work is poor to illegible even if copied by sight from another document, and drawing is difficult. Oral spelling for these individuals is normal, and their finger tapping speed is below normal. This shows that there are problems within the fine motor skills of these individuals. People with developmental coordination disorder may be dysgraphic. Writing is often slanted due to holding a pen or pencil incorrectly