There's a lot of truth to what you're saying. Golding puts civilized boys on a deserted island, and they quickly become barbaric in their survival mode. The boys who hold on to the idea of rescue as a real possibility are also the boys who represent some of the best parts of civilization: intelligence, logic, innocence, and friendship for the sake of friendship rather than necessity. Jack's "friends" aren't true friends...they are afraid of him and they find safety in numbers.
Ralph is the first to be chosen as leader by the boys. He represents logic and reason. He is the one who orchestrates the shelter, the food, the water, and the signal fire. He is also the first to initiate a friendship with Piggy, whom the other boys make fun of due to his weight and his glasses.
Piggy represents intelligence. He and Ralph make a great team as far as leadership and keeping the boys grounded in their civilization. Ralph and Piggy are the last to lose all their clothing items as well, whereas the others almost immediately have shed all that makes them civilized British boys on the outside, so the slippery slope to barbarism on the inside is a much easier transition.
Simon represents innocence. Although he is also very sensitive and intuitive, he is the innocent on the island and the first to die. Ironically, he dies the same day he spent so much time in the forest face to face with the pig head and where he came to understand that the only danger on the island is within the boys themselves...the dark and evil side of human nature.
These three boys are the ones who are targeted as the first to die--Simon, then Piggy, and if the fire set to draw Ralph out hadn't been so large bringing the Navy ship, Ralph would have been next. Without civilization, there is complete chaos, and yes, it could happen in our world if we lose focus on civilized discourse. However, without being stranded on a deserted island, it would take a much longer time since there are so many who remember "the rules".