Gotcha, if Marcell Dareus or Gerald McCoy were sitting there you would have a point, but Bosa is probably the only DL who goes in the top 5, maybe even the top 10. Nkemdiche has alot of good traits but no real production, he'd be underwhelming in the top 5, I like DeForest Buckner alot too and I wouldn't be surprised if he rose into the top 10, but again, doesn't really have the look of a top 5 pick to me.
You might as well just say you'd prefer us to draft a Luck-caliber prospect but saying it doesn't make it so, and if there aren't any dominant DE's or DT's what are you supposed to do?
My point is that most of the top prospects are either underwhelming (Nkemdiche, Ramsey) or play positions that aren't impact positions for us (RT, non-pass rushing LB, CB), so we might as well take a shot on a QB.