Considering AA gives the dom. F seats away to Elites and high fares, indicates they think they can't sell it for more money. They may be wrong here.

UA's E+ is only extra legroom, no width. UA gives E+ to its Elites and high fares, so same story there. It's more of a perk to encourage people to choose them over the competition. Smart move, IMO, because if you put UA against LH or the others, it's a clear differentiator.

The only ones who have gotten away with charging for Premium Economy are BA and VS. Probably because not only is there more legroom, but also more width (which is why I think AA may be wrong in giving its domestic F seats away). BA is essentially 4 classes now, and VS 3.

So there might be a market for this type of Premium Economy. The question is will it cover the cost of the real estate, and how will it offset sales? Some people will buy PE instead of Y, while others may buy PE instead of J.