Well if we're going by simple body count then the Nats will never compete with the likes of the Yankees, and I'm fine with that. Wearing a fashionable cap or jersey doesn't make one a fan, and the Yankees have an enormous number of "fans" of that caliber and always will.
I think it's too soon to lay claim to being "one of the best" as far as fanbases go, but this series clearly disproves the idea that DC will never support a baseball team. Like most cities, winning cures all. Big "duh" there.