It has to, absolutely, have had an impact.
I mean, when club cricketers such as Glenn Maxwell and Dave Warner earn $1m and $.75m for a month of "work" in the IPL - it completely changes your incentives as a cricketer. The most you can earn for playing Shield Cricket (and the attendant, interminable and unwatched 50 over matches) for a WHOLE SEASON is $100,000, after money was diverted from these traditional forms of cricket to our version of the IPL, the "Big Bash".
By Australian standards, $100,000 a year is nice, but, unless you seriously live to play cricket, hardly worth giving up most day jobs for, given the lack of security. So, it is rational to treat longer form cricket as a fall back, concentrating your energies on smashing the ball out of the park against the bowling machine all week, knowing your salary from 20/20 is enough to keep you living well - international selection is just a bonus.
But, Australia's fall from grace has been way too steep to be caused by one thing alone. I think you can trace the dismantling of this side back several years to when Clarke was 'anointed' as successor to Ponting as captain. Since then there has been incident after incident with player after player having a falling out with Clarke. Every time there is an incident of disharmony, Clarke seems to be the common denominator.
Never was it in the script for us to play back to back Ashes series without at least two of Katich, Hussey and Ponting in the side, however, for whatever reason they all had disagreements with Clarke, and, in an extraordinary coincidence, none of them are playing.
Back to the cricket, and, while I tend to go easy on umpires having stood in plenty of games (at a much lower level!) myself, the decision to overturn Agar's not out decision in the second innings was utterly baffling. The ICC should investigate the decision process behind this decision, offer an explanation, or stand the video umpire down. There appeared not to be a shred of evidence - audio, deviation, or hot spot to see Agar be given out - truly baffling.