>>6614008My guess would be that /toy/ is a smaller, slower board. Less traffic means less potential participants meaning less great gift givings. The diverse yet insular sub-niches of collectors and board generals also breaks up the amount of potential people who would want to get involved in something like that as well.
That said, /toy/ used to have some good secret santas, but a lot of regulars seemed to have stopped coming here in the past few years. Without regulars and such, there's even less cohesion across the board leading to less people willing to give to the secret santa.