There are no young guns around anymore. In the early 1990s you had guys like Ponting, Langer, Hayden, Slater, Martyn etc banging out centuries and 1000 run seasons. Where is even one young (20-23 year old) gun bastman who is racking up the hundreds and stringing together 1000 run seasons? Even just one of them. Something has either gone terribly awry, or we were just blessed with an outstanding generation of players.
There have been a few young batsmen who've been scoring well without dominating in what's been a bit of a quick bowler's season like Pommersbach, Bailey and Shaun Marsh had a decent start. But the fact of the matter is that the state teams don't seem to be be picking them; they're following the trend of the Aussie team in picking guys later and sticking with established players. These guys are performing well so no reason to drop them. In the earlier days, the Aussie team wouldn't have given a second glance to blokes older than 30 so the state teams had no motivation to pick them. With older guys getting picked, the state sides have greater motivation to keep picking them where they might have looked to the younger guys in previous years.
To this end, it just so happened in the early 90's that there was a whole generation of younger players making their mark as a whole generation of older players left the game. Right now, the older (Katich, Langer, Haddin, Noffke, D Hussey, Hodge, McDonald, Jaques) batsmen are doing the job so younger guys aren't getting much of a look-in for their states. Additionally, you have to admit, it's been an unusually fruitful season for bowlers who can bat with Noffke, Nicholson and Gillespie well and truly in the runs. This further negates the need to pick younger batsmen. The good thing is, when they have been picked, they've done well; Hughes from NSW has been quite good, that new Davis bloke for WA just scored a ton against an attack with the most in-form state opening bowler right now.
The issue isn't limited to batsmen either; all of the quick bowlers doing well are older blokes like Bolly, Denton, Noffke, Inness, Bracken, etc. So the squeeze is on even more for spots. To be honest, as I wrote in my article, the only real worry right now is in the spin department; not a lot there at the moment.