The point is - even if you take the PPV's out of the picture - you dont build ratings by blowing your best fueds/matches in one unnanounced night. You build those fueds over a period of time, attracting more people to the show. Then, when you decide to get to the pinnacle of the fued you make sure every wrestling fan in the world knows its going to happen and has a chance to watch. The RVD/AJ/ and RVD/Hardy matches will still be good, but its never as good as seeing it the first time around. It looses some of the buzz around the match-up.
As they have done it, this weeks TNA scored a 0.5 - so its done worse in the ratings rather than get any new viewers to the product.