To take another poster's example, a house bought for £100K in 1950 may now be worth just under £1M and be exempt from inheritance tax. But, the inflation adjusted value of that £100K capital today is £994,996. Other than the utility of having had somewhere to live for the past 65 years and only having had to pay for the building's upkeep, the actual profit in a £100K to £1M home over the example given by another poster is next to nil.
You are forgetting that the person who bought for £100K in 1950 put down a deposit of £5k, on which they'd paid tax, and borrowed £95K, on which they hadn't. Then they would have got MIRAS tax relief on their mortgage interest for the entire length of their mortgage so paid zero tax on their repayments.
Add that to the fact that around my way, West London, a house bought in 1951 for £2K was recently sold for £2.5M, a £100K house in 1950 would have been a 20 bed mansion in Kensington, and would sell for around £150M.
Sorry, but your facts and figures are so divorced from reality, that it's embarrassing.
I'm not ashamed to admit that I will benefit from the recent change in IHT, but I'm not stupid enough to try and pretend I've paid tax on the money I will leave in my estate. It will be mainly London house price inflation and has been neither earned nor taxed. That is a fact!