There won't be another one because they managed to botch a fucking texture pack for the existing games. He's probably rightly worried that a new title wouldn't be up to the high standard of the second one, as you should be.
And he asked fans to reiterate just how hard they want a new game, which is a nice PR move, but makes sense when the HD collection has sold pretty badly. Also gives him some time to fuck about doing Kojima things.