>But they don't want your $20 to watch the game on TV, they want ABC's $3 billion (or whatever) for the right to charge you whatever ("watch these ads") to see the game.
I had to look this up, but it appears that the price per year for NBA television rights was well under $1 billion/year(http://www.insidehoops.com/nba-tv-contracts.shtml). From 2002 to 2007, TNT paid about 2.2 billion in total. ESPN/ABC paid around 2.4 billion for the same time period. Per year, that's around $300 million each. Even assuming a 50% increase in cost, that comes out to around $450 million/year per network for 2012.
The biggest irony is that the NBA could be making an absolutely insane amount of money selling directly to the consumer. At $30 per month for a 6 month season, all they need to do is sell around 5 million total subscriptions to equal the net income from the television contracts. I'm positive that the NBA could get those kinds of numbers, especially with European or Chinese basketball fans who might not be able to see the games any other way.
All the NBA needs to do is actually make the service work, and provide the games that are already being televised.