Obviously the esthetics of Surf Music and Deathmetal differ. In terms of musical skill there's no question the Beach Boys were ahead of the curve in their own time, when bands such as those you mention and favor could not exist.
I can listen to Spem in Allium and laugh the lack of musical knowledge of others, but nobody thinks alike now, do we? Let's not dismiss the past on account of said music of the past being so different from what we listen to now.
How does this work sit with you, all of you out there, listening to this?: