i don't disagree
The fact that there are other games they could show at the same revenue shows there isn't a huge amount of value to diminish in the first place. What matters to them is eye's on the TV, not so much the names of the team generating the ratings. If University X draws 2x what University Y does, they're going to air University X.
ESPN should be doing everything they can to squeeze every dollar out of it's exsisting contract since there is no certainty that they will get the next one. If FOX or another company decides to swoop in, then ESPN will have wasted their own money to devalue a product that they aren't even gaurenteed to retain at the new lower value. If the current BE schools feel slighted by ESPN, they would be more apt to take similar money elsewhere to feel like their product potential is being maximized.
i don't disagree with your logic, but i think ESPN would take it one step further, which i am trying to allude to. assume the BE tv contract runs through 2015 (or 3 years), and ESPN values the contract at $300M a year ($600M in total), and gives the big east $50M a year (or $150M). however, in the next 7 years ESPN still values the contract at a present value of $300M per year, and knows they would have to give the BE $150M a year if they agreed to a contract right now (BE wants a bigger slice of the bigger pie, as do most). since the ESPN knows the contract is a profit of $150M a year, and the BE said no to them to negotiate with other networks, ESPN could try to kill the value of the tv contract (i.e. less viewers = less leverage for the BE), so that when negotiations open, the BE is only worth $200M and the BE can only get $100M max.
if you are ESPN, and there is $300M of value out there that your competitor can steal from you, and you have essentially been told you are going to lose the contact (BE told ESPN we will bid out), would you not try to steal some of the value (i.e. help initiate the move of Pitt and Syracuse to the ACC since they add some of the most value, and diminish the viewership of the BE which means lower ad dollars). by lowering the add dollars, you are lowering the potential ad revenue NBC sports and CBS has to play with, making it tougher for them to operate. in theory, some of the $300M should be going to ESPN anyways since they could replace the UCONN vs. Rutgers game with a game from another conference they have a contract with, and SU and Pitt are going to ACC (which ESPN holds contract with). if you are ESPN, and you don't feel you can get the contract extended or there at least risk you will lose the contract, you don't want to let NBC or CBS take the $300M in value you helped to create.
again, this is just from my experience and schooling, but your's might be better. not saying your logic is off, cause in most cases i would agree with it, but not when big money/egos is at stake