I'll bet the actual reason for the wacky model is something dumb, but basic, like using an autorigger exclusively, without doing a manual edit of the model after applying the mocapped textures. Not doing manual passes is way faster, but the results tend to be shit.
Note that Asian (primarily Korean and Chinese, since they tend to have the largest output nowadays) games also use the autorigger; however, they have one notable advantage. Namely, hordes of poorly paid (thus, cheap) junior animators (a junior animator barely earns more than a basic QA tester, and QA is the lowest rung) to manually edit the models.