It seems to me like NBC got a better deal for what they spent on The Jay Leno Show last week than ABC did with its 10pm shows.
Week of October 5-11, 2009
The Jay Leno Show average: 1.7 rating adults 18-49
Cost: $2 million
(conventional wisdom is that TJLS costs $100 million for a 46 new weeks in 52 week season or ~$400,000/hour)
Castle, Eastwick, the forgotten, Private Practice, 20/20 average: 2.2 rating adults 18-49
Cost: $6.3 million
(assumes $2 million/hour for dramas for 22 episodes plus 8 repeats (for a cost of $1.46 million/hour) and $400,000/hour for 20/20, but ABC will need to spend to program another 22 weeks of shows at 10pm, see below)
So NBC achieved 77% of ABC's ratings while spending 32% of the money.
That same calculation going to look a lot worse for ABC when they go into repeats. Their Monday-Thursday ratings will drop but the cost stays the same (since repeats are already factored in).
ABC will, of course, receive extra revenue from Private Practice and Castle DVDs, and any foreign licensing from them. They don't get any of that from the forgotten or Eastwick, since they're not the producer of the shows. But how much more will they have to spend to program the other 22 weeks of 10pm shows?
Update: If anyone thinks that ABC isn't running these same sorts of calculations themselves (but with much better data) you're kidding yourself.