I've almost finished Christopher Kraft's excellent book "Flight". He was part of the STG (Space Task Group) of the late 50's.
He writes he felt NASA became a bureaucracy not after Apollo but years before (in 1964-1965): when NASA was transfered from Langley to Houston (and MCS from the Cape to Houston).
All of a sudden, many more people came in and disputes were bound to happen between the Centers.
He also writes North American Aviation wasn't really taking care of the Apollo spacecraft (prefering to entertain NASA people with long parties). They were aked to get serious and back to the drawing board (years before the Apollo 204 fire) as the STG had noticed a difference between Mc Donnell Douglas and NAA.

Raoul