It's a slippery slope. As far as I can tell they reproduce asexually, and faster than rabbits. They mutate rapidly as well. Zeiss Ikons begetting Kodaks, Voightlanders (sp?), Ensigns, Agfas, etc. Pretty soon your house will be an Ark with cameras marching 6x6 and 6x9 and the little baby 6x4.5's until you can't see the floor. Then they'll evolve into more complex bellowed beast like Fuji's and Mamiya TLR's, until they finally shed their primitive bellows for boxes, eventually becoming SLR's. Sure there will be a few coelecanth-like large format view cameras lurking in the hidden away places of your closet, but the MF SLR's will rule the world.
At least that's my story, and I'm sticking to it.