"Multitasking" is a much misunderstood concept.
The popular buzz word at KPMG in the mid-2000's was "multitasking." Everyone had to multitask well. It made me smile when I started reading articles around 2008 and 2009 that pointed out humans aren't capable of effective multitasking, and trying to do so decreases overall productivity. The GTD movement recognized that multitasking is bullshit.
We can either (1) Do one project really well in a short amount of time; (2) do multiple projects poorly in a short amount of time; or (3) do multiple projects really well in a long amount of time. Note that doing multiple projects really well in short amount of time is not a a viable option.
The confluence of client pressure to get projects done quickly, plus pressure to keep fees low, equals an environment where staff are encouraged to "multitask" (do multiple projects well in a short amount of time). This sets them up for failure in an environment in which they cannot learn.