Explain the pun

Old skiers never die They just go downhill

"Old soldiers never die-they just fade away" is an old saying that was popularized by General Douglas MacArthur (1880-1964) in his farewell address to Congress on April 19, 1951. Many parodies of the saying have been made.

"Old skiers never die-they just go downhill" is a jocular one-line saying that has been printed on many posters and T-shirts. The line has been cited since at least 1973; in 1975, the saying was advertised on a bumper sticker in Ski magazine.

The skier when down hill like he failed horribly if you want to have an explanation i am here because why the heck not