I'm sure Super League will still have value to SKY, but I'm not so sure it will have much increased value. Afterall they couldn't be bothered to put in a half decent bid for the World Cup rights by all accounts, so are they that fussed? As others have said, SKY seem to be rebalancing what they do away from over-reliance on sport, moving to a more balanced portfolio of channels. I imagine they are also looking to make money by selling on their own productions worldwide (a la BBC & ITV), than simple forking out on sports rights.
Anyhow, I would suggest anyone thinking BT might come in and bid a stupid amount for RL should think twice. BT signed a 4 year deal for £152m for the rights to the Aviva Premiership, JP Morgan 7s and european matches featuring Aviva Premiership sides. Apparently, £100m of that amount is for exclusive broadcast rights of european cup rugby competition, which is £30m more than SKY were prepared to pay the organisers of the HEC. So a good deal. This £100m carrot is what the English clubs are dangling in front of the Celtic nations to get them to agree to sign up to the new competition that the Premiership and Top 14 have organised. However, what it does suggest is that BT see little value in the rights for the Aviva Premiership per se.
I would have thought BT are looking to use the european competition to significantly expand their brand into other european market. Not sure that RL can offer them the same scope.
Sky treat our game seriously during the summer months. I'm sure if our next Northern Hemisphere World Cup was in June/July, they would be seriously interested.
As it stands, they have the Premier League, Champions League and Heineken Cup at this time of the year.