Why Eric Brown did not become a rear admiral

Why was Eric 'Winkle' Brown not promoted to rear admiral?

CVA-01's cancellation undercut his planned naval-attaché path, and his frustration with the decision contributed to his leaving the Navy.

Brown had been considered for service in the United States as naval attaché. In this account, CVA-01's cancellation made a Fleet Air Arm officer appear less appropriate for that role, and Brown left the service in frustration rather than continuing toward flag rank.