I work with several interns who are exceptionally smart, capable, and well-read.
I do see an issue with some where they hop around and don't finish long form projects. But I think thats a function of college where racking up resume filler seems more important these days.
About the short projects. I am a high school senior, and I sometimes jump around between projects / don't finish them because I sometimes struggle to see the point in finishing them. The only projects I can complete are ones where I can see the point of them and how they will be used.
I do see an issue with some where they hop around and don't finish long form projects. But I think thats a function of college where racking up resume filler seems more important these days.