Why early automatic boilers saved relatively few crew

Did automatic boilers fitted during a refit greatly reduce the crew requirement?

Only modestly, because early automatic systems still needed substantial supervision in case they failed.

Early automatic boilers still needed enough people nearby to intervene if the controls failed. The resulting crew reduction was therefore modest. More mature oil-fired boilers and modern gas turbines are contrasted with those early systems, because their operating problems are better understood. Monitoring machinery from computer screens represents a later level of confidence in automation.