[gholling]

Because manufacturing... Otherwise you have to CNC the whole thing and it makes it really expensive.

[liminalsunset]

I suppose you have a point. It was probably extruded along the fins like this (coming straight in/out of screen):

__|||||||___(fan)____

Then they would have to CNC the edges off to create the mounting ears anyway and cut the slots in the fins. I suppose they could just make the gaps larger but this is probably getting into the details...