[teosis]

They have a lot of good resources. Vampires, werewolves, mummies...

But the games they release are weird. what's the reason?

[Mr.Z4]

While I can't really speak to the tabletop/RPG side I think it is because to use all those resources you mentioned you need a story. Having a good story written takes time and money something a lot of companies do not want to spend they just want profit.