As far as I am concerned IHT is completely separate from operating profit. I appreciate that farming is hard and they deserve to make money but to not mitigate against IHT is just silly.
Maybe part of the problem is just how daft our economic system has become. Something is worth what somebody will pay for it. The value of a business is often related to its earning potential (which can include things like growth and future potential). Ignoring the exceptions like land sale with planning permission for developments that means the value of farm land should be in relation to it's earning potential.
One of the main arguments against the initial IHT budget changes that farmers were using is that their businesses have high asset values in relation to their earnings potential which to me suggests their land is over-valued.
When you can sell an asset and get higher income from bank interest than working the asset I suspect that asset is over-valued.
But: sometimes people retain emotional links to assets eg I know somebody who rents out their house and they could get higher income (and less work) if they sold the house and put the money in a bank savings account. But they believe the house has capital value growth potential long term.