Because you need the cash up front to buy the ingredients - seed, fertiliser, diesel - all more expensive than last year. (Not saying you’re wrong though.)

That is the easy part, any farmer these days is already selling their crop before it is planted. They let investors and insurance take the major risk, between the two they are guaranteed to break even, and if there is anything left over because of a good year (there normally is) that is profit. if investors are not willing to buy their expected crop at the price needed to break even the farmer doesn't plant at all.

The land is going to be your largest expense in the typical case. If you truly can't come up with the money for inputs, how are you going to carry the land? You can often push your land costs until after harvest, but if you don't have the harvest to pay for it... And if you know you won't be able to put a crop in due to budgetary constraints, why wouldn't you rent it out to another farmer? There are lineups of hungry farmers ready to spend whatever it takes to find new ground to work.

I find it hard to believe that land is going to lay fallow this year specifically because of what's going on. Certainly people are adjusting what they plan to grow to optimize for the situation. That is definitely happening.

With the high temps at the poles this year already. I have my doubts that Mother Nature is going to play nice.