I wrote earlier that I support your idea of a broadly applied IHT, but I think this is an optimistic model based on my very cursory searches and guesses.
Is this mean individual wealth or the mean estate at death? ONS says wealth decreases steadily after age 64, and the mean is likely to be significantly higher than the median.
The wealthy pensioners are mostly already paying IHT and someone said that’s only 5% of estates above £325K pp or £650K per couple. So what are the true mean and median? The 5% statistic, which I have frequently heard, suggests a much lower figure.
If we suppose the mean pensioner estate is £250K pp, which still seems high in this light, 5% is just £12,500. Excepting those who pay normal IHT and ignoring the issue of bandings, this brings in around £7B, and I don’t think it is politically palatable: it is Theresa May’s Death Tax.
To make the concept politically viable I think you need very, very low bandings and then the revenue is minimal.
I would like to be wrong - I would like for everyone to accept that we need to pay a social care tax/insurance either annually or at death.