But it's never been a voluntary creative aim, not since the very first show. It just grows from all of the shows. Whatever the writers say is irrelevant since for the purposes of nailing what canon is (as opposed to fanon); it's whatever appeared on the screen. The only leeway is whether or not you include the movies. It's more amusing if we do since they tend to contradict themselves, the shows and other movies, as well as inventing lots of extra stuff which gets the fans tied in knots.