I never said they will ever matter to the story (that would be silly, if you ask me). All I said was that we do not have much in the way of evidence for the statement that „[t]jere are only three SG members still alive” (although the continued survival of elements from the ”old guard” would undermine your point about justice having been done already, and the fact that some SG members may still not be accounted for would mean that this is entirely possible).