Why staff service did not guarantee a plum naval appointment

Would War Office or Admiralty service normally earn a returning captain a plum appointment such as commodore?

It might, but only depending on his performance, the period, and his political connections; no appointment was automatic.

Staff work did not create an automatic path to a broad pennant. A returning captain's prospects depended on his performance, the conventions of the period, and his political connections. A commodore appointment could be a reward or a useful employment without becoming an entitlement. It remained a temporary command appointment rather than a change in the officer's substantive Royal Navy rank.