I'm sorry, but that just proves it -- one composer completely ripped off the melody of the other.
He may have done it subconsciously/unconsciously, but that's practically the same tune. A few cosmetic differences doesn't hide the fact that it's the same melody.
I'm legit surprised that no one ever got sued for this. If I had to guess, I'd say that the He-Man composer ripped off Mancini (who did Reminigton Steele), but I don't know for sure when one or the other theme first aired.
Again, it may well have been done unintentionally (the one who ripped off the other probably heard the other melody, then, during composing, it came to him -- and he thought that it was inspiration, not a subconscious memory).