And it depends on how one rides in the drops. I see many riders using the drops with little or no elbow bend. They'd actually be faster on the hoods with their forearms horizontal. Cylinders have terrible wind resistance. If you're going to make the effort to ride in the drops, get deep into them and bend your elbows. I descend that way in the drops unless I'm trying to go slow.

I agree about the vintage thing. When I was a kid, I always rode in the drops. Now I'm more likely to do the level forearm thing on the hoods.

Clip-ons are the way to really get the energy down. I'm higher with clip-ons then in the drops with a full tuck, but I descend faster because of having hidden arms. It took me a long time to realize that, because it doesn't feel faster.