Silver + Gold 5

I was just curious why people who constantly play at a poor level in Silver 5 and Gold 5 don't move down to Bronze, or Silver. It just doesn't make sense to me. I understand that if you continue to lose that you're ELO will go down further and further to the lower ranks but your actual rank wont. Why should someone who was lucky to get Gold in provisionals deserve to get the border and skin at the end of the season if they really play at a bronze level... If someone could explain I'd love to hear.