Note: This is just a thought experiment, not saying this scenario would be probable, likely, or even necessarily possible.

This is sort of a 'Trading Places' type scenario.
Tptb pick a certain date and percentage:
• If >x% of plebs are vax'd by date y, release the Blue Variant: the Nonvax'd are wiped out and the matrix continues with a more compliant base.
• If <x% of plebs are vax'd by date y, release the Red Variant: the Vax'd are wiped out, and we see how deep the rabbit hole goes.
Tptb place their bets, and the winner gets 1 fresh new dollar bill.
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Either way there is massive population reduction, and the human lineage goes through an evolutionary process according to a decision based on free will (sort of, enough for the satanic powers that run things).
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(Yes there are other scenarios, yes people could just end up eating each other instead, this is just an idea outside of ones that have been discussed perhaps.)