Yes, the government subsidizes corn and soy. That doesn't mean that alternatives cheaper than the unsubsidized price of these inputs couldn't be found. If subsidies are removed, innovation may follow.

There are also cases where the government restricts crop production.

http://sites.gsu.edu/us-constipedia/wickard-v-filburn-1942/

https://thecounter.org/biden-administration-farmers-conserva...