I have heard some sports like netball say they get a good deal from Sky that allows them to put money back into the sport, but you have to weigh that up against the loss of interest from fans who don't have Sky. I know I watch more sport when it's on free to air as it's much easier to access.
Many countries such as Australia have laws that important sports events must be free for all to view. For example much of the spring racing carnival has to be on free to air tv. I do wonder if the loss of interest in recent years in our local sports is because we don't promote them to the public like they do. The number of people who have Sky is decreasing and so a smaller and smaller audience is viewing these events.