>Anyone can do this level of work - they just need to actually learn it.
Sorry, that's like saying with enough math practice, any kid could perform at the level of young Terry Tao (e.g. teaching himself calculus at 8, winning a gold medal at the International Math Olympiad at 12). Some people are just intrinsically talented at certain things, and no amount of hard work in people lacking those intrinsic talents will get them to that level. This is indisputable when it comes to athletic talent; everyone would agree that no matter how much an average tall person practices basketball, they will never play at the level of Michael Jordan, LeBron James, or even the lowest ranked NBA player [0], for that matter. Artistic and intellectual talent is no different.
[0] https://old.reddit.com/r/todayilearned/comments/1oxpng5/til_...
I didn't say anyone can become Michelangelo. I said anyone can do this level of work.
That is, the exact same thing he did when he was 12, which is a master study. He didn't create the design - he copied a previous work and added color to find out what Schongauer's thought process was when making the original piece.