BH and Pfitzy you have fair points. But it isn't as clear cut as that.
With the exception of Sam Carter who has performed at a fairly consistent level the general theme is that many of those knocking on the door (e.g. Jones, Skelton, etc.) have started the year very strongly, however have failed to maintain that form to an extent, and theirs is probably on a slight decline if anything.
On the other hand, incumbents like Horwill, Genia and AAC (Adam Ashley-Cooper) have started their seasons a little slowly, however appearing to be starting to hit form now.
It's not a black and white comparison. I'm sure Link has a look and thinks "X player has had a full off-season, been refreshed and then had a full pre-season and has subsequently hit the ground running. Y Player on the other hand was on tour until December last year. He got home mid-December, had a short break, then joined in pre-season late and subsequently has started the season slowly and gradually improved".
I'm certainly not discounting form, we just need to consider that sometimes it's not a like for like comparison and jumping out the blocks is easier for those who haven't been playing for the Wallabies year round.