Please explain if it is possible for some men to have receding hairlines that don't eventually lead to male pattern baldness?
Genetic. All normally-masculinized men lose the hair on our temples at about age 20. In some men, especially the more hairy-chested, it continues and progresses to male pattern baldness. Look around you and you'll see the variability. A physically fit man (photoguy) looks incomparably better than a non-fit man regardless of who has hair where. Best wishes.