I have no problem with their age - they're still great cricketers - wasn't meant to be an insult at all...
Again, I think it's like the great Windies of the 70's and 80's - there was something in the water that produced an amazing group of cricketers - but it won't last, they cannot play forever, and the replacements cannot be of the same quality (and from what's been seen, they're not even close). Most of the succesful newcomers have been 30 somethings themselves
Warne will go on for as long as he can, as he has nothing else. The drugs ban probably did him some good. McGrath's time off probably did't hurt his body either.
But if Aust keeps up this trend towards ridiculous pitches that any mug can bat on, two things will happen - Ponting's average will keep rising and the nonsense about him being the best since Bradman will continue, and McGrath and Warne's careers will be ended more quickly