This is already how things work in the US: you only need to file if your estate is greater than 11.5MM as of 2020 [1].
"As a result, only about 2,000 estates per year in the US are currently liable for federal estate tax." [2]
The argument that it "discourages living frugally" is just complete nonsense.
[1]: https://www.irs.gov/businesses/small-businesses-self-employe...
[2]: https://en.m.wikipedia.org/wiki/Estate_tax_in_the_United_Sta...