Lore

The magic used to sustain Pincara/Nemeton needs a blood sacrifice. This cannot the same magic that makes clones.
The clones were originally supposed to be that blood sacrifice. If you're telling me the clones also need a blood sacrifice to make, then why bother making them in the first place?
I can tell you that the Clone Production Facility somewhere in Nemeton was definitely made from blood, but they have to source the magic that makes the clones from something that isn't blood (at least, not their blood).