[saalweachter]

I would also add:

3. We massively overproduce grains in the average year because falling short one year is really, really bad.

Since we're going to have too much grain most years, we might as well feed the excess to livestock and turn it into meat. In bad years we can reduce the amount of livestock to keep the available grain constant.

The same goes for ethanol.

Efficiency is the often the enemy of security, and food security is very, very important.