And the sunflowers was toss too. Bioplastic is made from a wide variety of stuff.
2% of the world supply of polymers!!!!! WOW. At what percentage of the cost? (Hint, look up online the price per tonne of something like polyethylene and then pick one polymer derived from a "green" raw material.)
Please do some sums, very, very simple maths and tell me where the other 98% is coming from, what other than crude oil, if crude oil stayed in the ground. You are living in fantasy land.
You need a raw material source of in the order of 400 million tonnes per annum. What combination of raw materials are you suggesting that might be? That also needs to be in addition to what the world already produces, pretty obviously.
Oils are loved by industry - actually liquids are, they are very very easy to handle, also natural oils are very uniform and are not contaminated by masses of stuff that is of no use, unlike all the other lunatic stuff used, such as cellulose. Press some seeds, de-water the oil, job done. This also ignores the vast amounts of input for any natural product.
What the hell anyone would do with all of the oil-seed expeller/cake, Christ alone knows.
What industry needs is a source of short-chain hydrocarbons. That is not satisfied by much outside of plant oils and natural, crude oil.
You are seeing a minute part of the entire story. You are living in a dream world with no knowledge of the maths or the chemistry.