No reason why they can't leverage the packages into mainly sky and a game a week elsewhere. I don't see how a Sunday 3pm game on Amazon impacts sky showing Friday and Thursday games one jot.
I think people fail to realise how little content anyone actually wants, outside football, Sky has.
Even the cricket is a channel of repeats plus the winter tests are usually at night.
I doubt they would even want to show old super league highlights if SL went elsewhere - which are still a source of good cheap programming.
SL should be using all the leverage they have.