Pixar could afford MoCap or any tech they wanted.
So If Pixar had 17 rigs for one mesh
,it's just cause that's the way they wanted it done.
Not cause that's the way Pixar had to.

DAZ Poser rigs
Some of it's they don't know how to rig.
Some of it's they rig for diffrent versions.
Some of it's compromise for Morphs so the rigs work with a gaint warrior and a small elf.
Some of it's for conforming cloths.

only DAZ Poser ,make human has morphs from boys to girls monsters & conforming cloths.

to do this they compromise on rigs.

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The Artist that will fight for decades to conquer their media.
Even if you never know their name ,your know their Art.
Dark Sphere Mage Vengeance