Back in the day, video game developers didn't have the memory available to make a game take 40 hours to complete. So, they were made more difficult to compensate for the length. Also, these kids aren't necessarily gamers. I bet if you took a group random 40yr-olds, the gameplay wouldn't be much better.
I remember seeing a react video on Mega Man for the NES, and one guy did pretty well against Bombman. He would have beaten the level on the next try. Even though he had never played a Mega Man game before, he was a gamer, and I think that's the big difference here.