I don't believe he was intending the plane to fly supersonic. Instead he was talking about using the design of the wings because they have a larger volume.
What's the use of a supersonic plane that doesn't fly supersonic?
Edit. It's unclear what your defence of the concept using this tactic achieves. The whole article talks of this as for supersonic flight. There are fewer issues with subsonic flight for this idea, though many (see above and below) remain.
The wings of a wide body aircraft would have larger volume, the wing surface area of a 474 is about double that of a concord, the A380 is nearly triple.