Its not even just about merchandise, though. Being family-friendly gets them the kind of sponsors that they couldn't hope to land with a PG13 product, let alone something closer to the Attitude era. Look at who they can get at this point - 7-Eleven, Pepsi, Gillette... Those kind of sponsors mean a lot more money than Slim Jim and the latest video game release.
With some of the problems that the WWE is facing - overall PPV buyrates going down, TV ratings aren't that strong, live attendances aren't that strong, DVD sales are weak, secondary programming seems to be in the dumps - they are not going to mess with those key revenue streams. Sponsors and key merchandise movers are more important to the WWE than ever before. You have to remember that McMahon can't simply do whatever he feels at this point, because he is beholden to those investors. If he decides to do something that is going to cut into those revenue streams that remains strong, he better have a good reason and alternative streams to replace them.
WWE stock is floating around the $9 mark. It was double that a year ago. It tanked partly because they decided to stop paying a dividend, but they aren't doing great business overall. Looking at the most recent investor meeting notes, its not like they have a lot on the horizon that is going to turn things around. They are going to pop a huge buy rate for WM 28 and then what? They are going to continue to lose old stars over the next couple of years, which is what McMahon partly blames for the issues over the past two years.
I hope the WWE makes a change to the product. I am damn near done with it, so its pretty much the only way I'm going to keep bothering with it. I just can't see it.