IMO its common sense. Bowling quality was just lower in the 2000 to early 2010s period and the batsmen made merry. Shoaib, Bond and Asif were the only consistently worldclass bowlers around aside from McGrath and they all broke down half the time. Pollock declined 2003 onwards. WI's pace legacy had ended.
Look at the great bowlers who played most of a decade:
70s - Lillee, Roberts, Holding
80s - Imran, Marshall, Hadlee, Garner, Walsh
90s - Wasim, Waqar, Ambrose, Walsh, Donald, Pollock, McGrath
2000s - McGrath
2010s - Steyn, Anderson and Philander if you count them