Would you make a deal for say $25 million over 20 years if you knew that by waiting a year or two you could make $50 million over 20 years? You have to put yourself in the shoes of Jerry Jones to really answer that question because I'm sure Jerry Jones has all the money he needs to maintain his lifestyle indefinitely. So he can wait for the best deal to come to him as soon as the big corporations start offering him big money when the economy improves. If you look at it that way, he is making the smart choice financially.
Now let's think about what would happen if the temporary name was meaningful. Like maybe Tom Landry Stadium. How mad would some people get if the name was Tom Landry Stadium and then two years from now Jerry had a press conference to announce that that name was changing to AT&T Stadium or Capital One Stadium? There would be some people seriously upset about something like that going down. That is exactly why you choose a name that is completely nondescript and forgettable.