>the US has a law that erases the tax bill for dead people
That is true, but there is a theory, applied very weakly, that supports this. The idea is that a decedent's estate is subject to a wealth tax on its fair market value, therefore to also subject the unrealized gains within the estate to income tax would be double taxation, which is to be avoided. The flaw is that the exemption from the estate tax is relatively high (something like $13,000K), so there would not be any double taxation is most cases, but it's treated that way nonetheless.
In the country I live the 401k equivalent is taxed yearly on gains (and again as income when I retire), and I think that is fine - I get a world class society in return (you guessed right, it is a Nordic country)
so the answer is yes.
However, i did not go as far as proposing anything. You are assigning value on my statement.
I merely pointed out that it is a mute point to say that you can not use your unrealized gains.
When those unrealized gains are spread across 10s-100s of millions of people it's fine because statistically gains are always being realized. As those holdings get further concentrated that stops happening.
Of course, as long as the tax is progressive. Custodians of assets almost all charge an annual feel on unrealised gains, it’s hardly a foreign concept…
The oldest trick in the book is to use unrealized gains as collateral for loans - we even have banks specializing in this.
Oh, and the US has a law that erases the tax bill for dead people - you'd be stupid not to use this trick.