Only about 4% of all estates paid any inheritance tax even before the changes. I never understand why it is such a big deal when it affects so few people in practice.
It is political - just like the fact that all the big corporations pay no corporation tax is also a political football. The IHT change will affect so few people, and with the many changes to trusts over the years much of the tax planning that went on in this area has actually ended up costing more in tax.
Much about taxation is political, eg the 50% tax rate - this increased the tax take by little if anything. In fact the tax take went up when the rate was dropped to 45% (for many reasons). This is not a political comment but what I see at the coalface and read about in the boring tax statistics that float through my work emails.
The biggest tax take by a massive margin is PAYE/NI from those that are employed. So from UK govt point of view all the big cos employing people means a massive jump in tax take irrespective of whether they are paying CT. CT has been reduced in any event and there are many other tax incentives for cos to remain in UK. This is partly because Ireland for example has a CT rate of 12.5%.
All the treasury notes published on or shortly after budget day include an impact statement of who is affected and who much the tax take will change (yes I do read them - I am paid to).