Virgin will have wanted to make sure that they got a decent guarantee about access to channels; otherwise they would've left themselves at quite a disadvantage - having no channels of their own with which to bargain in any future carriage negotiations.
Do you really think their channels really gave them much clout when it came to regular carriage negotiations? Living, Challenge, Bravo and Virgin1 vs Sky Sports, Sky One, Sky News and Sky Movies.....?
When Sky left cable a few years ago it did cause many people to move over to Sky... how many would do that if Living suddenly disappared from satellite?
You're right though that the security they've bought now for the company is a very good thing. Personally I'm surprised they got the deals and the money