Maybe it was the case, a long time ago, that the very rich accumulated their wealth by "living frugally", but it is certainly not the case anymore. Neither is the case that the estate tax discourages saving is just nonsense: at least in the US, the estate tax doesn't even apply is your estate is under $11M. [1]
> "As a result, only about 2,000 estates per year in the US are currently liable for federal estate tax." [2]