Many times these long term contracts come with large amounts of cash up front, as is the case with the Texas rangers new 20 year $3billion deal with Fox Sports.
It doesn't take effect until 2015, but the Rangers received $160 million cash up front and an equity stake in Fox Sports Southwest.
That article also goes on to state the viewership of a team like the Yankees on the YES network (318,000 average) vs a smaller market team like the Royals (32,000). Taken in that context, the Pittsburgh deal may not be all that bad.
It may not be the best thing for parity in the league, but considering many teams are getting large front loaded contracts, equity stakes in TV networks that can be worth more than their franchises, and predictable cash flow, these deals can be a huge win for organizations.