There is availability on VX because the markets they compete in have better offerings. UA's p.s. service is better for J/F than VX's F service. AA's probably is too, though I haven't tried it. The VX service has at least one element that is better than CO's transcon option - pitch/seat - but that's just for CO/DL/B6, not the others. And to suggest that the greater pitch equates to greater value only addresses one of several components of valuable service. That the seats remain available simply shows that there is not demand for them, despite the fact that they may be better than other carriers in some regards. I guess the travelling public - especially those paying to be in the pointy end of the plane - really does evaluate their decision on many different criteria, not just cost