I think it depends a lot on the situation. We've played around 40 players this year in tests. That is a huge number and most of those changes have been forced due to injuries.
We've already got 4 and a half forced changes to the 22 from the test two weeks ago against Argentina (I've counted Samo as a half as he has some sort of injury but would have been fit enough to play if required).
It's hard to fit in unforced changes when you've already got that level of disruption to the team.
NZ do it differently to us. They plan to have depth at international level. If they can this weekend Vito will get 20-30 minutes of game time. Vito is behind Thompson but he is being given time on the park to develop depth. Cheapening the All Black jersey? Our NZ brothers don't think so. They plan to bring people through so when injury strikes they have match-hardened, experienced back-ups.
Look at what we did in the first two tests this year. Against Scotland we picked players who played Super rugby the Saturday before. Then some players even played the Wales test - a Super game and two tests in seven days. Before the Scotland game I posted that we should prepare two different teams for those matches so that there was a minimum of seven days between games for each 15 (benches could have been different). I was roundly criticised for cheapening the jersey. We continued on through the Wales campaign and then the Rugby Championship picking what Deans thought was the best available team every week and more and more of our best players were crocked. Effectively we cheapened the jersey anyway because a whole lot of guys that the selectors didn't rate in June now have Wallaby caps. Some of them have even played quite well.
Had we planned from the start to rotate the squad through the Wales/Scotland games, perhaps picked our top squad for the Bledisloe's and then rotated through the rest of the RC we might well have had less injuries because of better rest but we certainly would have had more of our best players available for this weekend. We might have had the 20+ injuries but they would not have occurred to so many of our first choice players. Would we have lost more games? We'll never know.
That is not the whole story - you have to ask why we have so many injuries on the practise paddock for example - but its a significant part of our injury story. Lack of planning and failure to develop depth until we are forced to by injury is just not the way to manage the Wallabies in this era where you play 15 tests in about 25 weeks.
One thing I confidently predict: NZ will give McCaw and Carter sabbatticals next year and will cope just fine. Because they are planning and adding to depth already and will have things nicely covered. They'll be missed, but it won't turn into a disaster because they've planned for it. We, on the other hand......