Brent, I've never carried a "wrap around" external, but I have carried a Dana external quite a bit. To me, the vertical fiberglass wands on the Dana look like they perform exactly the same function as a wrap around external. They very effectively transfer load towards the front of the hipbelt. I'm guessing that is the answer -- the wrap arounds evolved into the Dana external. Even that sophisticated frame with it's cult following didn't sell well enough to stay in production. It's a pity.
