The comparison between de DF 28 and the schooner HP is correct, but not fully fair. The HP can come with a single tall mast in Sol style, but the DF cannot come in schooner style. In that comparison the difference in polars in the weak directions and windspeeds would diminish and the gains in the strong  directions and windspeeds would widen even more. Furthermore, given the same construction and fit out maturity the HP will weigh less. No contest there. And its single "outrigger" has so much more useful space that it may be hard to combat the temptation to stow it and even out that inherent weight advantage.

Also in the accomodation I see no limitation inherent to the HP design. The tri has to accomodate mast step and board and it has to leave enough space for pivot points on two sides. In addition a tri has to turn a berth into a shallow cave to allow a cockpit on top of it. A HP does not have these constraints. A tri simply cannot win, useful volume wise.