He was the reigning world champion in those pics.
The question posed is why didn't he wear the stripes on his sleeve after he was world champion.
You have the right to wear the jersey in the discipline in which you won it, until the next championship, but you can have the stripes on your sleeve after you are reigning champion.
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You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.