Not always. BEWD and Dark Magician are interesting phenomenons because they were pretty useless early on compared to faster threats like Summoned Skull and then outclassed completely by cards like BLS, but they got a whole slew of cards to support them. BEWD got Burst Stream of Destruction, White Dragon Knight (don't actually remember what it was called), and a few others, while Dark Magician got Dark Magician Girl, and a bunch of cards that did stuff with a bunch of "Dark Magician" cards in play. So it depends on the monster, I guess.