Complex sentence: But as McCoy pointed out (1957), a "Nomad" was a "wanderer," and Roper likewise stayed on the move with his career, and their friendship and interaction as men became a lasting theme of the strip.
Split into simpler sentences: But as McCoy pointed out (1957), a "Nomad" was a "wanderer," and Roper likewise stayed on the move with his career. Their friendship and interaction as men became a lasting theme of the strip.