Is this first hand or second hand knowledge? ie. have you practiced for 5 years yourself?

and after a little more practice she’ll be like davinci, and after a little bit of practice on the harmonica i’ll be able to compose like Beethoven. and after a little bit of practice cutting himself orange socks will be able to perform open heart surgery.

As much as someone who can’t draw shouldn’t say “it can’t be done” someone who can’t draw shouldn’t say “it can be done”. Accept that art involves skills that lay people don’t appreciate no matter how many museums they visit or art books they skim read. Your faith in her ability to reach yuumei is baseless. Ask yuumei how well did she draw at 15. That will be your marker as to whether whats-her-face can reach yuumei’s level.

Maybe someone should make a post on concept art .org or something asking how much work needs to be done to get to a certain level of competence and post it as an article here. Some of them are pretty open to the idea that certain people should just give up.