So basically what he's saying is because Bethesda doesn't have any current games on the Wii, the Wii U is of limited value to them as a platform to bring either existing or new games to. That is, until the Wii U has a proven uptake in adopters.
Had the Wii been a platform that Bethesda games could have worked on, then they would have had a following on the platform that might have given them a reason to put games on the Wii U. Since the Wii wasn't a platform for Bethesda games, the Wii U currently would not be able to successfully support their games. Either people who own a Wii are going to purchase the game for a PC, Xbox 360, or PS3, or they're not going to purchase it at all.
He's not bemoaning the power of the Wii U, he's simply stating the business case why Bethesda is not actively planning on the release of any titles on the Wii U.
