Nor has anyone suggested that they are.
The original poster simply said that it would be in WotC's self-interest to reach out to Paizo and try to convince them (presumably by offering them cash or a superior business model) to support the new edition of D&D.
While I agree that this would be in WotC's best interest, I have to concede that I don't see an upside for Paizo. Even if WotC doubled the current combined sales of D&D and Pathfinder, Paizo's support material would have a hard time matching the volumes they're doing now as a standalone game.
Paizo has never hid the fact that the Adventure Path's make up the bulk of their business. Rule books share a secondary position with just about every other product line. And they could still sell those, just as modules, if the environment supported it.
In the end I would be just as happy to see Pathfinder continue alongside D&DN. I just hope D&D embraces the opensource approach again. I mean, they are selling game rules - which in and of themselves can't be copyrighted. So in a way D&D has always, and always be, "open" whether WotC likes it or not. What's the gain in not embracing it?