I disagree. I think after the first few months, pay per views would make just as much, if not more money, because feuds would be fresher and built up better. If I order a show to see Triple H vs. Kennedy (or something else new) and then three weeks later they're fighting again on pay per view, I'm not going to order that second one unless the rest of the card is really worth my money. And plus, I'm only getting rid of one of the major belts; it's not like I'm saying that only the WHC and WWE Tag Titles are on the line. You could always have the champion in a non-title match too..I think a lot of younger fans especially just watch to see their favorite wrestlers and could care less who the champions are.
EDIT: I guess another solution would be that if both titles are on the line, one of them should be a rematch from the previous PPV (no 3-peats though, unless it's a REALLY great feud). I just hate seeing first-time title matches taking place with less than 4 or 5 weeks build (see Triple H vs. Edge).