UPDATE: Mike Licht prognosticates:
In prior administrations, many political appointees were actually capable of doing the work they were paid for, so absorption into the merit system civil service made sense. The prime (and often sole) qualification of Bush bureaucrats was ideological purity; Job One was destruction of the agencies in which they were posted, so the actual work could be farmed out to the corporations of plutocrat pals.
We normally subscribe to the adage ”Never attribute to malice that which can be adequately explained by stupidity.” While stupidity is certainly an inexhaustible resource, eight years of data indicate the outrageous inefficiency and departmental destruction inflicted by Bush “Schedule C” appointees has been purposive behavior. “Burrowing” is an attempt to extend this losing legacy into the Obama years.