What will happen to the price of plastic when demand for oil starts reducing for mobility and heating with the move to electricity energy?

Flying pigs will deliver our food directly from the production point, no more need for packaging.

Not much; I used to think the same thing. But there are many ways to make the same chemicals from bio sources, either directly grown (corn or soy as feedstocks) or more processed, or bioengineered so bacteria convert some bio input to the desired chemicals