Why has the president's staff grown so much in the last seventy years? many presidents enter office with a commitment to cutting the size of their staff, but is this realistic? why or why not? why do presidents rely more on the white house staff than on the various other offices in the executive office of the president? why don't presidents rely more heavily on their cabinets?

They use their cabinet for more important meetings. The staff is there for various reasons, whether it be security and plenty of other issues. Many presidents have cut the second they're in office. It is realistic, for many different reasons. Budget spending during the first few months is usually terrible due to all the different cuts and plans. The WH staff is more directed to all the needs of the president, it would take longer to reach out to a dedicated branch to get the proper sustainable answers/help.