Putting reliability aside, turbopumps also increase the weight of the engine and weight limits on the Apollo missions were tight.
Apollo 8 Manned Space Flight Film Report 1968 NASA; SA-503, CSM-103Jeff QuitneyPublished on Dec 20, 2018A story of the first manned mission to leave Earth's orbit and orbit the moon. The 50th Anniversary of the Apollo 8 launch is on Friday, December 21, 2018.[snip]