its not _that_ hard -_-. just that a lot of music on violin played solo is acquired taste... just like many flutes, or drums.
the real sound comes when its played with other instruments in concert. it doesnt need years of practice it needs patience the right setting and an extra joint on ur pinky :p
I think it's hard in comparison to non-bowed string instruments. Even someone on their first day playing a guitar can pluck a single open string and not have it sound terrible, but getting a decent tone when bowing an open string on a violin is something that might take months for someone to do even sometimes.
> it doesnt need years of practice
It absolutely requires years of practice to play the violin at an expert level. This is well documented.
> the real sound comes when its played with other instruments in concert
So in the violin repertoire, the Bach sonatas and partitas for unaccompanied violin, the Ysaÿe sonatas and the Paganini caprices are what, not real?
My experience may be a bit biased by having to listen to children attempting to learn the instrument.