Imagine if in any other industry it was normal to completely turn over the majority of your workhorse staff because they're by design expendable and temporary.
Imagine if ILM or other VFX studios just completely changed half their staff mid-project. Or in a non-creative position like an accounting branch in a company constantly teaching wave after wave of new replacement hires on how their books are set up and what gets categorized where.
It would be a fucking mess. Why is seemingly only games like this?