Part of why I can understand the homesickness thing is that for a lot of these kids it's their first time living away from home. For any of you that went to college straight away at 18 you'll know this. You're pumped up for your first few weeks at school, but then you might have a set back, or a teacher comes down on you or you suffer some sort of disappointment and you don't have that familiar support system in your family and friends for the last 18-19 years there to pat you on the back and tell you it's ok.
The big difference between professional sports in the USA and AUS is that the kids here in the states usually have 3-4 years of college to get them ready for the pro leagues so that by the time they get there they are used to being away from home......for a lot of these kids all they have is the club and whatever people they meet locally, but it's not the same as home. The kids that are strong can get past it, the weaker ones succumb.
Talent aside, maybe we're better off in Caddy's case if after 2 years away he can't make a new home 3 hours north by plane.