Springkink Mystery

Too much has been going on in RL for me to take in much of springkink. But now that I look at it (briefly - 'cause I'm at work), the vast majority of stories seem to be about Kingdom Hearts (!) or Transformers (!!!).

Aren't these a video game and a rather simplistic kids' cartoon, respectively? Can someone explain why these might be so popular for the springkink treatment?

And here I thought that my much-expanded repertoire of manga knowledge would enable me to appreciate this stuff more effectively this time around ... .