For a while he was The Spare, second in line for the throne. An important if lesser position, with the prospect of getting the Top Job, if his brother were to meet with an accident. Then Charles married Diana and had two sons. That was Andrew demoted two places, followed by further demotion when William married and had a family.
In his naval career, his seniority increased automatically with time, and he could expect promotion at intervals. After he left active service, he still kept acquiring honorary positions which gave him a chance to wear his uniform (all the nice girls love a sailor) and make public appearances in his role as Military Man, even if not as Action Man any more.
Now he has been demoted again. Not a happy position for a bear of little brain.