Regarding players leaving and having family ties and girlfriends etc, I don't think it's really reasonable to expect every player to stay. Some of them are going to be lured home or even to other clubs away from home for any number of reasons. All you can really do is try to make your club as attractive as possible by building a strong culture and winning matches so that they have added incentive to stay.
What annoys me is why we've been so poor at luring big names back home. There's only two teams in SA, you'd think we would have a pretty good shot at picking up some quality SA talent. It's not like SA boys don't have family or girlfriends when they're recruited. But other than Betts, the only SA boys who were rated at all when we got them (Thompson and Jacobs) only fell into our laps when Port turned their noses up.
Losing the likes of Dangerfield, Tippett, Gunston, Davis, and potentially now Lever and/or McGovern would be a lot easier to stomach if we were able to attract quality SA boys back home at the same rate, or hell, even half the rate would be nice.