Well, depends on the math. $450 an acre of inputs can be a bit low for corn ground, and he didn't account for any rent payments. For most farmers, let's assume that of that 1000 acres of corn, he owns 100 acres. So, throw $250 an acre for rent on top of the $450 an acre (add in probably $50 in crop/hail/farm insurance), you're looking at $750 an acre of input costs.
200 bu corn @ $3 is what, $600 gross? Looks like a net loss of $150 an acre over an assume 900 acres, or $135,000 on those acres.
There are certainly farmers that are still racking in cash hand over fist, paid off ground, paid off machinery, crop share agreements with landlords, etc., but the reality is that the farm economy is on the 5th year of pretty shitty cash prices, outside of a few small time frames in each year where the crop could have been marketed for a profit. And most farmers aren't going to forward contract 100% (hell, even 50%) of their expected production when we get summer price run ups because their crop is not made yet.
But yes, this death tax really won't affect many farmers. Some, sure, but not many. We've got a few guys locally that own 1500-2000 acres that it could hit, but that's pretty rare.