It's really not all that technical to draw hyper realistic art, it's just tedious as fuck. It's not like they draw the subject from memory, it would be impossible to that unless you are a savant.
If you want to dismiss the Miku drawing as autistic that's fine, but creating a memorable character design that people give a shit about is really hard and most artists never accomplish making a design like that their entire lives. My opinion of fanart is similar to my opinion of realism, most of the hard work was done for the fanart (the design). If you don't even have an interesting composition it's worthless.