Speaking here as someone who is now semi rural but ran a farm for 20 years.. it has always been much more expensive to live in the country - no public transport, no gas, septic tanks, very limited services (which our taxes pay for) etc.
However, I do not agree that farmers should be entirely exempt from IHT. This exemption was brought in, I believe, by the John Major government in 1992 (other versions had been around for a while but this government enacted it in totality) and it has been used as a tax loophole for years.
Equally, I think the exemptions should be clearer and the tax should only be implemented when a farm is sold, not upon inheritance by a family member.